1
|
García-García MJ. A History of Mouse Genetics: From Fancy Mice to Mutations in Every Gene. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1236:1-38. [PMID: 32304067 DOI: 10.1007/978-981-15-2389-2_1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The laboratory mouse has become the model organism of choice in numerous areas of biological and biomedical research, including the study of congenital birth defects. The appeal of mice for these experimental studies stems from the similarities between the physiology, anatomy, and reproduction of these small mammals with our own, but it is also based on a number of practical reasons: mice are easy to maintain in a laboratory environment, are incredibly prolific, and have a relatively short reproductive cycle. Another compelling reason for choosing mice as research subjects is the number of tools and resources that have been developed after more than a century of working with these small rodents in laboratory environments. As will become obvious from the reading of the different chapters in this book, research in mice has already helped uncover many of the genes and processes responsible for congenital birth malformations and human diseases. In this chapter, we will provide an overview of the methods, scientific advances, and serendipitous circumstances that have made these discoveries possible, with a special emphasis on how the use of genetics has propelled scientific progress in mouse research and paved the way for future discoveries.
Collapse
|
2
|
West JD, Tang PC, Everett CA, MacKay GE, Flockhart JH, Keighren MA. Re-evaluation of the causes of variation among mouse aggregation chimaeras. Biol Open 2019; 8:8/5/bio042804. [PMID: 31147312 PMCID: PMC6550066 DOI: 10.1242/bio.042804] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
The composition of adult mouse aggregation chimaeras is much more variable than X-inactivation mosaics. An early theoretical model proposed that almost all the extra variation in chimaeras arises, before X-inactivation occurs, by spatially constrained, geometrical allocation of inner cell mass (ICM) cells to the epiblast and primitive endoderm (PrE). However, this is inconsistent with more recent embryological evidence. Analysis of published results for chimaeric blastocysts and mid-gestation chimaeras suggested that some variation exists among chimaeric morulae and more variation arises both when morula cells are allocated to the ICM versus the trophectoderm (TE) and when ICM cells are allocated to the epiblast versus the PrE. Computer simulation results were also consistent with the conclusion that stochastic allocation of cells to blastocyst lineages in two steps, without the type of geometrical sampling that was originally proposed, could cause a wide variation in chimaeric epiblast composition. Later allocation events will cause additional variation among both chimaeras and X-inactivation mosaics. We also suggest that previously published U-shaped frequency distributions for chimaeric placenta composition might be explained by how TE cells are allocated to the polar TE and/or the subsequent movement of cells from polar TE to mural TE.
Collapse
Affiliation(s)
- John D West
- Genes and Development Group, Centre for Integrative Physiology, Clinical Sciences, University of Edinburgh Medical School, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Pin-Chi Tang
- Genes and Development Group, Centre for Integrative Physiology, Clinical Sciences, University of Edinburgh Medical School, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Clare A Everett
- Genes and Development Group, Centre for Integrative Physiology, Clinical Sciences, University of Edinburgh Medical School, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Gillian E MacKay
- Genes and Development Group, Centre for Integrative Physiology, Clinical Sciences, University of Edinburgh Medical School, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Jean H Flockhart
- Genes and Development Group, Centre for Integrative Physiology, Clinical Sciences, University of Edinburgh Medical School, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Margaret A Keighren
- Genes and Development Group, Centre for Integrative Physiology, Clinical Sciences, University of Edinburgh Medical School, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| |
Collapse
|
3
|
Tang PC, MacKay GE, Flockhart JH, Keighren MA, Kopakaki A, West JD. Selection against BALB/c strain cells in mouse chimaeras. Biol Open 2018; 7:7/1/bio030189. [PMID: 29330350 PMCID: PMC5829504 DOI: 10.1242/bio.030189] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
It has been shown previously that BALB/c strain embryos tend to contribute poorly to mouse aggregation chimaeras. In the present study we showed that BALB/c cells were not preferentially allocated to any extraembryonic lineages of mouse aggregation chimaeras, but their contribution decreased during the early postimplantation period and they were significantly depleted by E8.5. The development of BALB/c strain preimplantation embryos lagged behind embryos from some other strains and the contribution that BALB/c and other embryos made to chimaeras correlated with their developmental stage at E2.5. This relationship suggests that the poor contribution of BALB/c embryos to aggregation chimaeras is at least partly a consequence of generalised selection related to slow or delayed preimplantation development. The suitability of BALB/c embryos for maximising the ES cell contribution to mouse ES cell chimaeras is also discussed. Summary: BALB/c strain embryos contributed poorly to mouse aggregation chimaeras by E8.5. Selection appears linked to slow BALB/c development and might also explain the good ES cell contribution in BALB/c↔ES-cell chimaeras.
Collapse
Affiliation(s)
- Pin-Chi Tang
- Genes and Development Group, Centre for Integrative Physiology, Clinical Sciences, University of Edinburgh Medical School, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK.,Obstetrics and Gynaecology Section, Clinical Sciences, University of Edinburgh Medical School, The Queen's Medical Research Institute, 47 Little France Crescent, Edinburgh, EH16 4TJ, UK
| | - Gillian E MacKay
- Genes and Development Group, Centre for Integrative Physiology, Clinical Sciences, University of Edinburgh Medical School, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK.,Obstetrics and Gynaecology Section, Clinical Sciences, University of Edinburgh Medical School, The Queen's Medical Research Institute, 47 Little France Crescent, Edinburgh, EH16 4TJ, UK
| | - Jean H Flockhart
- Genes and Development Group, Centre for Integrative Physiology, Clinical Sciences, University of Edinburgh Medical School, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK.,Obstetrics and Gynaecology Section, Clinical Sciences, University of Edinburgh Medical School, The Queen's Medical Research Institute, 47 Little France Crescent, Edinburgh, EH16 4TJ, UK
| | - Margaret A Keighren
- Genes and Development Group, Centre for Integrative Physiology, Clinical Sciences, University of Edinburgh Medical School, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK.,Obstetrics and Gynaecology Section, Clinical Sciences, University of Edinburgh Medical School, The Queen's Medical Research Institute, 47 Little France Crescent, Edinburgh, EH16 4TJ, UK
| | - Anna Kopakaki
- Obstetrics and Gynaecology Section, Clinical Sciences, University of Edinburgh Medical School, The Queen's Medical Research Institute, 47 Little France Crescent, Edinburgh, EH16 4TJ, UK
| | - John D West
- Genes and Development Group, Centre for Integrative Physiology, Clinical Sciences, University of Edinburgh Medical School, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK .,Obstetrics and Gynaecology Section, Clinical Sciences, University of Edinburgh Medical School, The Queen's Medical Research Institute, 47 Little France Crescent, Edinburgh, EH16 4TJ, UK
| |
Collapse
|
4
|
Keighren MA, Flockhart JH, West JD. Survival of glucose phosphate isomerase null somatic cells and germ cells in adult mouse chimaeras. Biol Open 2016; 5:596-610. [PMID: 27103217 PMCID: PMC4874354 DOI: 10.1242/bio.017111] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2016] [Accepted: 03/22/2016] [Indexed: 01/22/2023] Open
Abstract
The mouse Gpi1 gene encodes the glycolytic enzyme glucose phosphate isomerase. Homozygous Gpi1(-/-) null mouse embryos die but a previous study showed that some homozygous Gpi1(-/-) null cells survived when combined with wild-type cells in fetal chimaeras. One adult female Gpi1(-/-)↔Gpi1(c/c) chimaera with functional Gpi1(-/-) null oocytes was also identified in a preliminary study. The aims were to characterise the survival of Gpi1(-/-) null cells in adult Gpi1(-/-)↔Gpi1(c/c) chimaeras and determine if Gpi1(-/-) null germ cells are functional. Analysis of adult Gpi1(-/-)↔Gpi1(c/c) chimaeras with pigment and a reiterated transgenic lineage marker showed that low numbers of homozygous Gpi1(-/-) null cells could survive in many tissues of adult chimaeras, including oocytes. Breeding experiments confirmed that Gpi1(-/-) null oocytes in one female Gpi1(-/-)↔Gpi1(c/c) chimaera were functional and provided preliminary evidence that one male putative Gpi1(-/-)↔Gpi1(c/c) chimaera produced functional spermatozoa from homozygous Gpi1(-/-) null germ cells. Although the male chimaera was almost certainly Gpi1(-/-)↔Gpi1(c/c), this part of the study is considered preliminary because only blood was typed for GPI. Gpi1(-/-) null germ cells should survive in a chimaeric testis if they are supported by wild-type Sertoli cells. It is also feasible that spermatozoa could bypass a block at GPI, but not blocks at some later steps in glycolysis, by using fructose, rather than glucose, as the substrate for glycolysis. Although chimaera analysis proved inefficient for studying the fate of Gpi1(-/-) null germ cells, it successfully identified functional Gpi1(-/-) null oocytes and revealed that some Gpi1(-/-) null cells could survive in many adult tissues.
Collapse
Affiliation(s)
- Margaret A Keighren
- Genes and Development Group, Centre for Integrative Physiology, Clinical Sciences, University of Edinburgh Medical School, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - Jean H Flockhart
- Genes and Development Group, Centre for Integrative Physiology, Clinical Sciences, University of Edinburgh Medical School, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| | - John D West
- Genes and Development Group, Centre for Integrative Physiology, Clinical Sciences, University of Edinburgh Medical School, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK
| |
Collapse
|
5
|
Lessons from mouse chimaera experiments with a reiterated transgene marker: revised marker criteria and a review of chimaera markers. Transgenic Res 2015; 24:665-91. [PMID: 26048593 PMCID: PMC4504987 DOI: 10.1007/s11248-015-9883-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 05/21/2015] [Indexed: 11/12/2022]
Abstract
Recent reports of a new generation of ubiquitous transgenic chimaera markers prompted us to consider the criteria used to evaluate new chimaera markers and develop more objective assessment methods. To investigate this experimentally we used several series of fetal and adult chimaeras, carrying an older, multi-copy transgenic marker. We used two additional independent markers and objective, quantitative criteria for cell selection and cell mixing to investigate quantitative and spatial aspects of developmental neutrality. We also suggest how the quantitative analysis we used could be simplified for future use with other markers. As a result, we recommend a five-step procedure for investigators to evaluate new chimaera markers based partly on criteria proposed previously but with a greater emphasis on examining the developmental neutrality of prospective new markers. These five steps comprise (1) review of published information, (2) evaluation of marker detection, (3) genetic crosses to check for effects on viability and growth, (4) comparisons of chimaeras with and without the marker and (5) analysis of chimaeras with both cell populations labelled. Finally, we review a number of different chimaera markers and evaluate them using the extended set of criteria. These comparisons indicate that, although the new generation of ubiquitous fluorescent markers are the best of those currently available and fulfil most of the criteria required of a chimaera marker, further work is required to determine whether they are developmentally neutral.
Collapse
|
6
|
Oishi H, Tsubaki T, Miyazaki T, Ono M, Nose M, Takahashi S. A bacterial artificial chromosome transgene with polymorphic Cd72 inhibits the development of glomerulonephritis and vasculitis in MRL-Faslpr lupus mice. THE JOURNAL OF IMMUNOLOGY 2013; 190:2129-37. [PMID: 23365086 DOI: 10.4049/jimmunol.1202196] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Systemic lupus erythematosus is considered to be under the control of polygenic inheritance, developing according to the cumulative effects of susceptibility genes with polymorphic alleles; however, the mechanisms underlying the roles of polygenes based on functional and pathological genomics remain uncharacterized. In this study, we substantiate that a CD72 polymorphism in the membrane-distal extracellular domain impacts on both the development of glomerulonephritis and vasculitis in a lupus model strain of mice, MRL/MpJ-Fas(lpr), and the reactivity of BCR signal stimulation. We generated mice carrying a bacterial artificial chromosome transgene originating from C57BL/6 (B6) mice that contains the Cd72(b) locus (Cd72(B6) transgenic [tg]) or the modified Cd72(b) locus with an MRL-derived Cd72(c) allele at the polymorphic region corresponding to the membrane-distal extracellular domain (Cd72(B6/MRL) tg). Cd72(B6) tg mice, but not Cd72(B6/MRL) tg mice, showed a significant reduction in mortality following a marked improvement of disease associated with decreased serum levels of IgG3 and anti-dsDNA Abs. The number of splenic CD4(-)CD8(-) T cells in Cd72(B6) tg mice was decreased significantly in association with a reduced response to B cell receptor signaling. These results indicate that the Cd72 polymorphism affects susceptibility to lupus phenotypes and that novel functional rescue by a bacterial artificial chromosome transgenesis is an efficient approach with wide applications for conducting a genomic analysis of polygene diseases.
Collapse
Affiliation(s)
- Hisashi Oishi
- Department of Anatomy and Embryology, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Tsukuba 305-8575, Japan
| | | | | | | | | | | |
Collapse
|
7
|
Eckardt S, McLaughlin KJ, Willenbring H. Mouse chimeras as a system to investigate development, cell and tissue function, disease mechanisms and organ regeneration. Cell Cycle 2011; 10:2091-9. [PMID: 21606677 DOI: 10.4161/cc.10.13.16360] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Chimeras are organisms composed of at least two genetically distinct cell lineages originating from different zygotes. In the laboratory, mouse chimeras can be produced experimentally; various techniques allow combining different early stage mouse embryos with each other or with pluripotent stem cells. Identification of the progeny of the different lineages in chimeras permits to follow cell fate and function, enabling correlation of genotype with phenotype. Mouse chimeras have become a tool to investigate critical developmental processes, including cell specification, differentiation, patterning, and the function of specific genes. In addition, chimeras can also be generated to address biological processes in the adult, including mechanisms underlying diseases or tissue repair and regeneration. This review summarizes the different types of chimeras and how they have been generated and provides examples of how mouse chimeras offer a unique and powerful system to investigate questions pertaining to cell and tissue function in the developing and adult organism.
Collapse
Affiliation(s)
- Sigrid Eckardt
- Center for Molecular and Human Genetics, The Research Institute at Nationwide Children's Hospital, Columbus, OH, USA.
| | | | | |
Collapse
|
8
|
Manuel MN, Martynoga B, Molinek MD, Quinn JC, Kroemmer C, Mason JO, Price DJ. The transcription factor Foxg1 regulates telencephalic progenitor proliferation cell autonomously, in part by controlling Pax6 expression levels. Neural Dev 2011; 6:9. [PMID: 21418559 PMCID: PMC3068069 DOI: 10.1186/1749-8104-6-9] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2010] [Accepted: 03/18/2011] [Indexed: 12/21/2022] Open
Abstract
Background The transcription factor Foxg1 is an important regulator of telencephalic cell cycles. Its inactivation causes premature lengthening of telencephalic progenitor cell cycles and increased neurogenic divisions, leading to severe hypoplasia of the telencephalon. These proliferation defects could be a secondary consequence of the loss of Foxg1 caused by the abnormal expression of several morphogens (Fibroblast growth factor 8, bone morphogenetic proteins) in the telencephalon of Foxg1 null mutants. Here we investigated whether Foxg1 has a cell autonomous role in the regulation of telencephalic progenitor proliferation. We analysed Foxg1+/+↔Foxg1-/- chimeras, in which mutant telencephalic cells have the potential to interact with, and to have any cell non-autonomous defects rescued by, normal wild-type cells. Results Our analysis showed that the Foxg1-/- cells are under-represented in the chimeric telencephalon and the proportion of them in S-phase is significantly smaller than that of their wild-type neighbours, indicating that their under-representation is caused by a cell autonomous reduction in their proliferation. We then analysed the expression of the cell-cycle regulator Pax6 and found that it is cell-autonomously downregulated in Foxg1-/- dorsal telencephalic cells. We went on to show that the introduction into Foxg1-/- embryos of a transgene designed to reverse Pax6 expression defects resulted in a partial rescue of the telencephalic progenitor proliferation defects. Conclusions We conclude that Foxg1 exerts control over telencephalic progenitor proliferation by cell autonomous mechanisms that include the regulation of Pax6, which itself is known to regulate proliferation cell autonomously in a regional manner.
Collapse
Affiliation(s)
- Martine N Manuel
- Genes and Development Group, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, UK.
| | | | | | | | | | | | | |
Collapse
|
9
|
Quinn JC, Molinek M, Nowakowski TJ, Mason JO, Price DJ. Novel lines of Pax6-/- embryonic stem cells exhibit reduced neurogenic capacity without loss of viability. BMC Neurosci 2010; 11:26. [PMID: 20178645 PMCID: PMC2837049 DOI: 10.1186/1471-2202-11-26] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2009] [Accepted: 02/24/2010] [Indexed: 11/18/2022] Open
Abstract
Background Embryonic stem (ES) cells can differentiate into all cell types and have been used extensively to study factors affecting neuronal differentiation. ES cells containing mutations in known genes have the potential to provide useful in vitro models for the study of gene function during neuronal differentiation. Recently, mouse ES cell lines lacking the neurogenic transcription factor Pax6 were reported; neurons derived from these Pax6-/- ES cells died rapidly after neuronal differentiation in vitro. Results Here we report the derivation of new lines of Pax6-/- ES cells and the assessment of their ability to survive and differentiate both in vitro and in vivo. Neurons derived from our new Pax6-/- lines were viable and continued to elaborate processes in culture under conditions that resulted in the death of neurons derived from previously reported Pax6-/- ES cell lines. The new lines of Pax6-/-ES cells showed reduced neurogenic potential, mimicking the effects of loss of Pax6 in vivo. We used our new lines to generate Pax6-/- ↔ Pax6+/+ chimeras in which the mutant cells survived and displayed the same phenotypes as Pax6-/- cells in Pax6-/- ↔ Pax6+/+ chimeras made by embryo aggregation. Conclusions We suggest that loss of Pax6 from ES cells reduces their neurogenic capacity but does not necessarily result in the death of derived neurons. We offer these new lines as additional tools for those interested in the generation of chimeras and the analysis of in vitro ES cell models of Pax6 function during neuronal differentiation, embryonic and postnatal development.
Collapse
Affiliation(s)
- Jane C Quinn
- Centre for Integrative Physiology, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK.
| | | | | | | | | |
Collapse
|
10
|
Chanas SA, Collinson JM, Ramaesh T, Dorà N, Kleinjan DA, Hill RE, West JD. Effects of elevated Pax6 expression and genetic background on mouse eye development. Invest Ophthalmol Vis Sci 2009; 50:4045-59. [PMID: 19387074 PMCID: PMC2763115 DOI: 10.1167/iovs.07-1630] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
PURPOSE To analyze the effects of Pax6 overexpression and its interaction with genetic background on eye development. METHODS Histologic features of eyes from hemizygous PAX77(+/-) transgenic (high Pax6 gene dose) and wild-type mice were compared on different genetic backgrounds. Experimental PAX77(+/-)<-->wild-type and control wild-type<-->wild-type chimeras were analyzed to investigate the causes of abnormal eye development in PAX77(+/-) mice. RESULTS PAX77(+/-) mice showed an overlapping but distinct spectrum of eye abnormalities to Pax6(+/-) heterozygotes (low Pax6 dose). Some previously reported PAX77(+/-) eye abnormalities did not occur on all three genetic backgrounds examined. Several types of eye abnormalities occurred in the experimental PAX77(+/-)<-->wild-type chimeras, and they occurred more frequently in chimeras with higher contributions of PAX77(+/-) cells. Groups of RPE cells intruded into the optic nerve sheath, indicating that the boundary between the retina and optic nerve may be displaced. Both PAX77(+/-) and wild-type cells were involved in this ingression and in retinal folds, suggesting that neither effect was cell-autonomous. Cell-autonomous effects included failure of PAX77(+/-) and wild-type cells to mix normally and overrepresentation of PAX77(+/-) in the lens epithelium and RPE. CONCLUSIONS The extent of PAX77(+/-) eye abnormalities depended on PAX77(+/-) genotype, genetic background, and stochastic variation. Chimera analysis identified two types of cell-autonomous effects of the PAX77(+/-) genotype. Abnormal cell mixing between PAX77(+/-) and wild-type cells suggests altered expression of cell surface adhesion molecules. Some phenotypic differences between PAX77(+/-)<-->wild-type and Pax6(+/-)<-->wild-type chimeras may reflect differences in the levels of PAX77(+/-) and Pax6(+/-) contributions to chimeric lenses.
Collapse
Affiliation(s)
- Simon A. Chanas
- Division of Reproductive and Developmental Sciences, Genes and Development Group, University of Edinburgh, Edinburgh, Scotland, United Kingdom
| | - J. Martin Collinson
- School of Medical Sciences, College of Life Sciences and Medicine, University of Aberdeen, Institute of Medical Sciences, Aberdeen, Scotland, United Kingdom
| | - Thaya Ramaesh
- Division of Reproductive and Developmental Sciences, Genes and Development Group, University of Edinburgh, Edinburgh, Scotland, United Kingdom
- Department of Clinical and Surgical Sciences, Ophthalmology Section, University of Edinburgh, Princess Alexandra Eye Pavilion, Royal Infirmary of Edinburgh, Edinburgh, Scotland, United Kingdom
| | - Natalie Dorà
- School of Medical Sciences, College of Life Sciences and Medicine, University of Aberdeen, Institute of Medical Sciences, Aberdeen, Scotland, United Kingdom
| | - Dirk A. Kleinjan
- Medical and Developmental Genetics Section, MRC Human Genetics Unit, Edinburgh, Scotland, United Kingdom
| | - Robert E. Hill
- Medical and Developmental Genetics Section, MRC Human Genetics Unit, Edinburgh, Scotland, United Kingdom
| | - John D. West
- Division of Reproductive and Developmental Sciences, Genes and Development Group, University of Edinburgh, Edinburgh, Scotland, United Kingdom
| |
Collapse
|
11
|
Gli3 is required autonomously for dorsal telencephalic cells to adopt appropriate fates during embryonic forebrain development. Dev Biol 2008; 327:204-15. [PMID: 19121302 DOI: 10.1016/j.ydbio.2008.12.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2008] [Revised: 12/09/2008] [Accepted: 12/10/2008] [Indexed: 01/07/2023]
Abstract
The Gli3 zinc finger transcription factor is expressed in developing forebrain, with the highest levels of expression in dorsal telencephalon. In Gli3(-/-) embryos the dorsal telencephalon is abnormally small and fails to develop dorsomedial telencephalic structures, including hippocampus and cortical hem, while the ventral telencephalon appears to expand. A hurdle to understanding the underlying mechanisms is that abnormalities of developing Gli3(-/-) telencephalic cells in Gli3(-/-) mutants result from a combination of their own cell autonomous defects and defects in the Gli3(-/-) cells that surround them. Here we used chimeras to identify some of the defects of Gli3(-/-) telencephalic cells that are likely to be autonomous by studying how Gli3(-/-) cells develop when surrounded by a majority of wild-type cells. We found that Gli3(-/-) cells are present in all components of the Gli3(-/-)<-->Gli3(+/+) chimeric forebrain, including dorsomedial structures, in proportions that either equal or exceed proportions found elsewhere in the embryo. Gli3(-/-) cells segregate from Gli3(+/+) cells to form many abnormal structures particularly in dorsal telencephalon. Gli3(-/-) cells in some locations are misspecified: in those parts of the dorsal telencephalon near to its boundaries with the diencephalon and the ventral telencephalon, mutant cells express sets of transcription factors expressed by wild-type cells on the other side of the boundary. Elsewhere in the dorsal telencephalon, in the diencephalon and in the ventral telencephalon, mutant cells express sets of transcription factors similar to those expressed by their immediately surrounding wild-type cells. We propose that an important cell autonomous action of Gli3 is to regulate the competence of dorsal telencephalic cells, preventing cells near to its boundaries expressing regulatory factors normally restricted to adjacent tissues.
Collapse
|
12
|
Everett CA, Keighren MA, Flockhart JH, West JD. Evaluation of triploid<-->diploid and trisomy-3<-->diploid mouse chimeras as models for investigating how lineage restriction occurs in confined placental mosaicism. Reproduction 2008; 134:799-809. [PMID: 18042637 PMCID: PMC2756007 DOI: 10.1530/rep-07-0285] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Human confined placental mosaicism (CPM), where the placental trophoblast is mosaic for a chromosome abnormality but the fetus is chromosomally normal, can cause problems for prenatal diagnosis, but its causes are poorly understood. Tetraploid↔diploid chimeras provide a model for the development of one type of CPM, but animal models for other types of restricted mosaicism are needed. The objective of the present study was to evaluate triploid↔diploid and trisomy-3↔diploid chimeric mouse conceptuses as new models for investigating the development of restricted mosaicism. Novel stocks of mice were generated to produce triploid and trisomy-3 embryos that could be identified by DNA in situ hybridisation to a chromosome 3 transgenic marker. Triploid↔diploid and trisomy-3↔diploid mouse chimeras were produced by embryo aggregation, and the contribution of triploid or trisomy-3 cells was analysed in the fetus and extraembryonic tissues. Only two trisomy-3↔diploid chimeras were analysed but trisomy-3 cells contributed well to all lineages, so these chimeras did not show restricted mosaicism. In contrast, triploid cells usually contributed poorly to all lineages in the ten 3n↔2n chimeras analysed. They contributed more to the primitive endoderm derivatives than other lineages and were present in the primitive endoderm derivatives of all ten chimeras, but excluded from fetuses and trophectoderm derivatives in some cases. This pattern of restricted mosaicism differs from that reported for tetraploid cells in tetraploid↔diploid chimeras, and triploid↔diploid chimeras may provide a useful model for the development of some types of restricted mosaicism in human conceptuses.
Collapse
Affiliation(s)
- Clare A Everett
- Genes and Development Group, Division of Reproductive and Developmental Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, Scotland, UK
| | | | | | | |
Collapse
|
13
|
Du X, Jensen P, Goldowitz D, Hamre KM. Wild-type cells rescue genotypically Math1-null hair cells in the inner ears of chimeric mice. Dev Biol 2007; 305:430-8. [PMID: 17397818 DOI: 10.1016/j.ydbio.2007.02.028] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2006] [Revised: 02/05/2007] [Accepted: 02/21/2007] [Indexed: 11/15/2022]
Abstract
The transcription factor Math1 has been shown to be critical in the formation of hair cells (HCs) in the inner ear. However, the influence of environmental factors in HC specification suggests that cell extrinsic factors are also crucial to their development. To test whether extrinsic factors impact development of Math1-null (Math1(beta-Gal/beta-Gal)) HCs, we examined neonatal (postnatal ages P0-P4.5) Math1-null chimeric mice in which genotypically mutant and wild-type cells intermingle to form the inner ear. We provide the first direct evidence that Math1-null HCs are able to be generated and survive in the conducive chimeric environment. beta-Galactosidase expression was used to identify genetically mutant cells while cells were phenotypically defined as HCs by morphological characteristics notably the expression of HC-specific markers. Genotypically mutant HCs were found in all sensory epithelia of the inner ear at all ages examined. Comparable results were obtained irrespective of the wild-type component of the chimeric mice. Thus, genotypically mutant cells retain the competence to differentiate into HCs. The implication is that the lack of the Math1 gene in HC precursors can be overcome by environmental influences, such as cell-cell interactions with wild-type cells, to ultimately result in the formation of HCs.
Collapse
Affiliation(s)
- Xiaoping Du
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, 855 Monroe Avenue, Room 515, Memphis, TN 38163, USA
| | | | | | | |
Collapse
|
14
|
Bryda EC, Pearson M, Agca Y, Bauer BA. Method for detection and identification of multiple chromosomal integration sites in transgenic animals created with lentivirus. Biotechniques 2007; 41:715-9. [PMID: 17191616 DOI: 10.2144/000112289] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Transgene delivery systems, particularly those involving retroviruses, often result in the integration of multiple copies of the transgene throughout the host genome. Since site-specific silencing of trangenes can occur; it becomes important to identify the number and chromosomal location of the multiple copies of the transgenes in order to correlate inheritance of the transgene at a particular chromosomal site with a specific and robust phenotype. Using a technique that combines restriction endonuclease digest and several rounds of PCR amplification followed by nucleotide sequencing, it is possible to identify multiple chromosomal integration sites in transgenic founder animals. By designing genotyping assays to detect each individual integration site in the offspring of these founders, the inheritance of transgenes integrated at specific chromosomal locations can be followed efficiently as the transgenes randomly segregate in subsequent generations. Phenotypic characteristics can then be correlated with inheritance of a transgene integrated at a particular chromosomal location to allow rational selection of breeding animals in order to establish the transgenic line.
Collapse
|
15
|
Manuel M, Georgala PA, Carr CB, Chanas S, Kleinjan DA, Martynoga B, Mason JO, Molinek M, Pinson J, Pratt T, Quinn JC, Simpson TI, Tyas DA, van Heyningen V, West JD, Price DJ. Controlled overexpression of Pax6 in vivo negatively autoregulates the Pax6 locus, causing cell-autonomous defects of late cortical progenitor proliferation with little effect on cortical arealization. Development 2007; 134:545-55. [PMID: 17202185 PMCID: PMC2386558 DOI: 10.1242/dev.02764] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Levels of expression of the transcription factor Pax6 vary throughout corticogenesis in a rostro-lateral(high) to caudo-medial(low) gradient across the cortical proliferative zone. Previous loss-of-function studies have indicated that Pax6 is required for normal cortical progenitor proliferation, neuronal differentiation, cortical lamination and cortical arealization, but whether and how its level of expression affects its function is unclear. We studied the developing cortex of PAX77 YAC transgenic mice carrying several copies of the human PAX6 locus with its full complement of regulatory regions. We found that PAX77 embryos express Pax6 in a normal spatial pattern, with levels up to three times higher than wild type. By crossing PAX77 mice with a new YAC transgenic line that reports Pax6 expression (DTy54), we showed that increased expression is limited by negative autoregulation. Increased expression reduces proliferation of late cortical progenitors specifically, and analysis of PAX77<---->wild-type chimeras indicates that the defect is cell autonomous. We analyzed cortical arealization in PAX77 mice and found that, whereas the loss of Pax6 shifts caudal cortical areas rostrally, Pax6 overexpression at levels predicted to shift rostral areas caudally has very little effect. These findings indicate that Pax6 levels are stabilized by autoregulation, that the proliferation of cortical progenitors is sensitive to altered Pax6 levels and that cortical arealization is not.
Collapse
Affiliation(s)
- Martine Manuel
- Genes and Development Group, Centres for Integrative Physiology and Neuroscience Research, Hugh Robson Building, George Square, University of Edinburgh, Edinburgh, UK.
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
16
|
Quinn JC, Molinek M, Martynoga BS, Zaki PA, Faedo A, Bulfone A, Hevner RF, West JD, Price DJ. Pax6 controls cerebral cortical cell number by regulating exit from the cell cycle and specifies cortical cell identity by a cell autonomous mechanism. Dev Biol 2006; 302:50-65. [PMID: 16979618 PMCID: PMC2384163 DOI: 10.1016/j.ydbio.2006.08.035] [Citation(s) in RCA: 176] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2006] [Revised: 08/11/2006] [Accepted: 08/15/2006] [Indexed: 11/20/2022]
Abstract
Many cerebral cortical neurons and glia are produced by apical progenitors dividing at the ventricular surface of the embryonic dorsal telencephalon. Other neurons are produced by basal progenitor cells, which are derived from apical progenitors, dividing away from the ventricular surface. The transcription factor Pax6 is expressed in apical progenitors and is downregulated in basal progenitors, which upregulate the transcription factor Tbr2. Here we show that Pax6−/− cells are under-represented in the cortex of Pax6+/+↔Pax6−/− chimeras early in corticogenesis, indicating that Pax6 is required for the production of normal numbers of cortical cells. We provide evidence that this underproduction is attributable to an early depletion of the progenitor pool caused by greater than normal proportions of newly divided cells exiting the cell cycle. We show that most progenitor cells dividing away from the ventricular surface in Pax6−/− embryos fail to express the transcription factor Tbr2 and that Pax6 is required cell autonomously for Tbr2 expression in the developing cortex of Pax6+/+↔Pax6−/− chimeras. Transcription factors normally expressed ventrally in the telencephalic ganglionic eminences (Mash1, Dlx2 and Gsh2) are upregulated cell autonomously in mutant cells in the developing cortex of Pax6+/+↔Pax6−/− chimeras; Nkx2.1, which is expressed only in the medial ganglionic eminence, is not. These data indicate that early functions of Pax6 in developing cortical cells are to repress expression of transcription factors normally found in the lateral ganglionic eminence, to prevent precocious differentiation and depletion of the progenitor pool, and to induce normal development of cortical basal progenitor cells.
Collapse
Affiliation(s)
- Jane C. Quinn
- Genes and Development Group, Department of Biomedical Sciences, Centres for Integrative Physiology and Neuroscience Research, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK
| | - Michael Molinek
- Genes and Development Group, Department of Biomedical Sciences, Centres for Integrative Physiology and Neuroscience Research, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK
| | - Ben S. Martynoga
- Genes and Development Group, Department of Biomedical Sciences, Centres for Integrative Physiology and Neuroscience Research, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK
| | - Paulette A. Zaki
- Genes and Development Group, Department of Biomedical Sciences, Centres for Integrative Physiology and Neuroscience Research, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK
| | - Andrea Faedo
- Stem Cell Research Institute, Dibit, H. S. Raffaele, Via Olgettina 58, 20132 Milan, Italy
| | - Alessandro Bulfone
- Stem Cell Research Institute, Dibit, H. S. Raffaele, Via Olgettina 58, 20132 Milan, Italy
| | - Robert F. Hevner
- Department of Pathology, University of Washington, Seattle, Washington, WA 98104, USA
| | - John D. West
- Division of Reproductive and Developmental Sciences, Genes and Development Group, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK
| | - David J. Price
- Genes and Development Group, Department of Biomedical Sciences, Centres for Integrative Physiology and Neuroscience Research, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, UK
- Corresponding author. Fax: +1 44 131 651 1706.
| |
Collapse
|
17
|
Jensen P, Smeyne R, Goldowitz D. Analysis of cerebellar development in math1 null embryos and chimeras. J Neurosci 2004; 24:2202-11. [PMID: 14999071 PMCID: PMC6730436 DOI: 10.1523/jneurosci.3427-03.2004] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The cerebellar granule cell is the most numerous neuron in the nervous system and likely the source of the most common childhood brain tumor, medulloblastoma. The earliest known gene to be expressed in the development of these cells is math1. In the math1 null mouse, neuroblasts never populate the external germinal layer (EGL) that gives rise to granule cells. In this study, we examined the embryonic development of the math1 null cerebellum and analyzed experimental mouse chimeras made from math1 null embryos. We find that the anterior rhombic lip gives rise to more than one cell type, indicating that the rhombic lip does not consist of a homogeneous population of cells. Furthermore, we demonstrate that math1 null granule cells are absent in the math1 null chimeric cerebellum, from the onset of their genesis in the mouse anterior rhombic lip. This finding indicates a vital cell intrinsic role for Math1 in the granule cell lineage. In addition, we show that wild-type cells are unable to compensate for the loss of mutant cells. Finally, the colonization of the EGL by wild-type cells and the presence of acellular gaps provides evidence that EGL neuroblasts undergo active migration and likely have a predetermined spatial address in the rhombic lip.
Collapse
Affiliation(s)
- Patricia Jensen
- University of Tennessee Health Science Center, Memphis, Tennessee 38163, USA
| | | | | |
Collapse
|
18
|
Abstract
Embryonic chimeras of the mouse are well-established tools for studying cell lineage and cell potential. They are also a key part of the analysis of complex phenotypes of mutant mice. By combining embryonic stem cell technology, molecularly tagged mutations and sensitive cell lineage markers, chimeras can provide invaluable insights into the tissue-specific requirement and the mode of action of many mouse genes.
Collapse
Affiliation(s)
- Patrick P L Tam
- Embryology Unit, Children's Medical Research Institute, University of Sydney, Westmead, New South Wales, Australia.
| | | |
Collapse
|
19
|
Buetow BS, Tappan KA, Crosby JR, Seifert RA, Bowen-Pope DF. Chimera analysis supports a predominant role of PDGFRbeta in promoting smooth-muscle cell chemotaxis after arterial injury. THE AMERICAN JOURNAL OF PATHOLOGY 2003; 163:979-84. [PMID: 12937138 PMCID: PMC1868260 DOI: 10.1016/s0002-9440(10)63457-8] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The carotid artery shows a common response to many forms of injury, including a rapid activation of smooth muscle cell (SMC) proliferation in the media and migration of SMCs into the intima to form a neointima. Platelet-derived growth factor (PDGF) is believed to play a role in this response to injury, but it has proven difficult to distinguish whether it is stimulating cell migration or cell proliferation, and whether the action is direct or indirect. To determine this, we created chimeric mice composed of both wild-type (WT) and marked PDGF receptor beta (PDGFRbeta)-deficient cells, and determined the consequences of PDGFRbeta expression for SMC participation in response to ligation of the left common carotid artery. The proportion of PDGFRbeta-/- SMCs increased 4.5-fold in the media and decreased 1.8-fold during formation of the neointima, consistent with migration of WT SMCs out of the media and into the intima, leaving the PDGFRbeta-/- cells behind. The fibrotic reaction in the adventitia, which does not involve cell migration, did not result in any change in relative abundance of WT and PDGFRbeta-deficient fibroblasts. We conclude that the most significant direct role of PDGFRbeta is to mediate responses that involve cell migration rather than proliferation.
Collapse
Affiliation(s)
- Bernard S Buetow
- Department of Pathology, University of Washington, Seattle, WA 98195-7470, USA
| | | | | | | | | |
Collapse
|
20
|
Hadjantonakis AK, Dickinson ME, Fraser SE, Papaioannou VE. Technicolour transgenics: imaging tools for functional genomics in the mouse. Nat Rev Genet 2003; 4:613-25. [PMID: 12897773 DOI: 10.1038/nrg1126] [Citation(s) in RCA: 132] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Over the past decade, a battery of powerful tools that encompass forward and reverse genetic approaches have been developed to dissect the molecular and cellular processes that regulate development and disease. The advent of genetically-encoded fluorescent proteins that are expressed in wild type and mutant mice, together with advances in imaging technology, make it possible to study these biological processes in many dimensions. Importantly, these technologies allow direct visual access to complex events as they happen in their native environment, which provides greater insights into mammalian biology than ever before.
Collapse
Affiliation(s)
- Anna-Katerina Hadjantonakis
- Department of Genetics and Development, College of Physicians and Surgeons of Columbia University, New York 10032, USA
| | | | | | | |
Collapse
|
21
|
Abstract
Cell ploidy in the ovarian follicle and corpus luteum was investigated by DNA in situ hybridization to a reiterated, chromosome 3 transgene in mice that were hemizygous for the transgene. This approach was first validated by analysis of mouse kidney, pancreas and liver control tissues, which contain different frequencies of polyploid nuclei. Polyploid nuclei (with multiple hybridization signals) were seen in histological sections of both ovarian follicles and corpora lutea. The frequency of polyploid nuclei in follicles showed no consistent relationship with age (between 6 weeks and 10 months) but polyploid nuclei were significantly more abundant in corpora lutea than follicles (6.3% vs. 2.5%). This implies that production of polyploid cells is more closely associated with differentiation of ovarian follicles into corpora lutea than with the age of the female. Polyploidy tended to be more frequent in corpora lutea of mice that had mated even if they did not become pregnant. This study has highlighted the presence of polyploid cells in the mouse ovarian follicle and corpus luteum and has identified mating as a possible trigger for polyploidy in the corpus luteum. Further work is required to determine the physiological role of polyploid ovarian cells in reproduction.
Collapse
Affiliation(s)
- Margaret A Keighren
- Genes and Development Group, Division of Reproductive and Developmental Sciences, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, UK
| | | | | | | | | | | |
Collapse
|
22
|
Collinson JM, Quinn JC, Hill RE, West JD. The roles of Pax6 in the cornea, retina, and olfactory epithelium of the developing mouse embryo. Dev Biol 2003; 255:303-12. [PMID: 12648492 DOI: 10.1016/s0012-1606(02)00095-7] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The roles of Pax6 were investigated in the murine eye and the olfactory epithelium by analysing gene expression and distribution of Pax6(-/-) cells in Pax6(+/+) <--> Pax6(-/-) chimeras. It was found that between embryonic days E10.5 and E16.5 Pax6 is autonomously required for cells to contribute fully not only to the corneal epithelium, where Pax6 is expressed at high levels, but also to the to the corneal stroma and endothelium, where the protein is detected at very low levels. Pax6(-/-) cells contributed only poorly to the neural retina, forming small clumps of cells that were normally restricted to the ganglion cell layer at E16.5. Pax6(-/-) cells in the retinal pigment epithelium could express Trp2, a component of the pigmentation pathway, at E14.5 and a small number went on to differentiate and produce pigment at E16.5. The segregation and near-exclusion of mutant cells from the nasal epithelium mirrored the behaviour of mutant cells in other developmental contexts, particularly the lens, suggesting that common primary defects may be responsible for diverse Pax6-related phenotypes.
Collapse
Affiliation(s)
- J Martin Collinson
- Division of Reproductive and Developmental Sciences, Genes and Development Group, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh EH8 9XD, Scotland, UK.
| | | | | | | |
Collapse
|
23
|
Kelly A, West JD. Developmental potential and survival of glycolysis-deficient cells in fetal mouse chimeras. Genesis 2002; 33:29-39. [PMID: 12001067 DOI: 10.1002/gene.10085] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Mouse embryos homozygous for a null allele of Gpi1 fail to complete gastrulation and die around E7.5. We produced E12.5 chimeric mouse conceptuses, composed of wild-type and homozygous Gpi1m/m null mutant cells to test whether the presence of wild-type cells allowed mutant cells to survive and, if so, whether they survived better in some tissue locations than others. Fourteen homozygous Gpi1m/m<-->Gpi1c/c chimeras were identified and these contained low levels of homozygous mutant cells in most tissues tested. Homozygous Gpi1m/m cells contributed better to the yolk sac endoderm and placenta than to the epiblast derivatives tested (retinal pigment epithelium, brain, tail, amnion, and yolk sac mesoderm). The depletion of mutant cells confirms that the gene acts cell autonomously, but the GPI deficiency is not always cell-lethal. When mixed with wild-type cells in chimeras, homozygous mutant cells can differentiate into many different cell types and survive until at least E12.5.
Collapse
Affiliation(s)
- Annemarie Kelly
- Genes and Development Group, Department of Reproductive and Developmental Sciences, University of Edinburgh, United Kingdom
| | | |
Collapse
|
24
|
Kapur RP. Colonization of the murine hindgut by sacral crest-derived neural precursors: experimental support for an evolutionarily conserved model. Dev Biol 2000; 227:146-55. [PMID: 11076683 DOI: 10.1006/dbio.2000.9886] [Citation(s) in RCA: 120] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Enteric ganglia in the hindgut are derived from separate vagal and sacral neural crest populations. Two conflicting models, based primarily on avian data, have been proposed to describe the contribution of sacral neural crest cells. One hypothesizes early colonization of the hindgut shortly after neurulation, and the other states that sacral crest cells reside transiently in the extraenteric ganglion of Remak and colonize the hindgut much later, after vagal crest-derived neural precursors arrive. In this study, I show that Wnt1-lacZ-transgene expression, an "early" marker of murine neural crest cells, is inconsistent with the "early-colonization" model. Although Wnt1-lacZ-positive sacral crest cells populate pelvic ganglia in the mesenchyme surrounding the hindgut, they are not found in the gut prior to the arrival of vagal crest cells. Similarly, segments of murine hindgut harvested prior to the arrival of vagal crest cells and grafted under the renal capsule fail to develop enteric neurons, unless adjacent pelvic mesenchyme is included in the graft. When pelvic mesenchyme from DbetaH-nlacZ transgenic embryos is apposed with nontransgenic hindgut, neural precursors from the mesenchyme colonize the hindgut and form intramural ganglion cells that express the transgenic marker. Contribution of sacral crest-derived cells to the enteric nervous system is not affected by cocolonization of grafts by vagal crest-derived neuroglial precursors. The findings complement recent studies of avian chimeras and support an evolutionarily conserved model in which sacral crest cells first colonize the extramural ganglion and secondarily enter the hindgut mesenchyme.
Collapse
Affiliation(s)
- R P Kapur
- Department of Pathology, University of Washington, Seattle, Washington, 98195, USA
| |
Collapse
|
25
|
EVERETT CLAREA, STARK MARGARETH, WEST JOHND, DAVIDSON DUNCAN, BALDOCK RICHARDA. Three-dimensional reconstruction of tetraploid<-->diploid chimaeric mouse blastocysts. J Anat 2000; 196 ( Pt 3):341-6. [PMID: 10853956 PMCID: PMC1468070 DOI: 10.1046/j.1469-7580.2000.19630341.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Studies of tetraploid<-->diploid (4n<-->2n) mouse chimaeras have demonstrated unequal contributions of 4n cells to different tissues of the midgestation conceptus. Such a pattern has also been reported in chimaeras as early as E3.5d, which show an enhanced contribution of 4n cells to the mural trophectoderm (Everett & West, 1996). In this study, sectioned 4n<-->2n and 2n<-->2n control chimaeric blastocysts were digitised and reconstructed in 3 dimensions (3-D). The 3-D images revealed only limited mixing of cells from the 2 contributing embryos of individual blastocysts in both chimaera groups. Consequently, the distribution pattern of the 2 cell types was dependent on the spatial relationship between the orientation of the blastocyst and the boundary between the 2 clusters of cells. The distribution patterns observed were not strikingly different for 4n<-->2n and 2n<-->2n chimaeras, each showing some transgenic positive cell contribution in all 3 identifiable developmental lineages. It was notable, however, that in all 4n<-->2n blastocysts at least some 4n cells were located adjacent to the blastocyst cavity. Such a consistent pattern was not evident in 2n<-->2n chimaeras. This study has demonstrated the value of 3-D reconstructions for the analysis of spatial relationships of 2 cell populations in chimaeric mouse blastocysts.
Collapse
Affiliation(s)
- CLARE A.
EVERETT
- Department of Reproductive and Developmental Sciences, University of Edinburgh, UK
| | | | - JOHN D.
WEST
- Department of Reproductive and Developmental Sciences, University of Edinburgh, UK
- Correspondence to Dr John D. West, Department of Reproductive & Developmental Sciences, Biomedical Sciences Site, University of Edinburgh, Anatomy Building, Medical School, Teviot Place, Edinburgh, EH8 9AG. UK. Tel.: +44 131 650 3112; fax: +44 131 650 6545; e-mail:
| | - DUNCAN DAVIDSON
- MRC Human Genetics Unit, Western General Hospital, Edinburgh, UK
| | | |
Collapse
|
26
|
Crosby JR, Tappan KA, Seifert RA, Bowen-Pope DF. Chimera analysis reveals that fibroblasts and endothelial cells require platelet-derived growth factor receptorbeta expression for participation in reactive connective tissue formation in adults but not during development. THE AMERICAN JOURNAL OF PATHOLOGY 1999; 154:1315-21. [PMID: 10329583 PMCID: PMC1866587 DOI: 10.1016/s0002-9440(10)65384-9] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The hypothesis that platelet-derived growth factor (PDGF) plays an important role in repair of connective tissue has been difficult to test experimentally, in part because the disruption of any of the PDGF ligand and receptor genes is embryonic lethal. We have developed a method that circumvents the embryonic lethality of the PDGF receptor (R)beta-/- genotype and minimizes the tendency of compensatory processes to mask the phenotype of gene disruption by comparing the behavior of wild-type and PDGFRbeta-/- cells within individual chimeric mice. This quantitative chimera analysis method has revealed that during development PDGFRbeta expression is important for all muscle lineages but not for fibroblast or endothelial lineages. Here we report that fibroblasts and endothelial cells, but not leukocytes, are dependent on PDGFRbeta expression during the formation of new connective tissue in and around sponges implanted under the skin. Even the 50% reduction in PDGFRbeta gene dosage in PDGFRbeta+/- cells reduces fibroblast and endothelial cell participation by 85%. These results demonstrate that the PDGFRbeta/PDGF B-chain system plays an important direct role in driving both fibroblast and endothelial cell participation in connective tissue repair, that cell behavior can be regulated by relatively small changes in PDGFRbeta expression, and that the functions served by PDGF in wound healing are different from the roles served during development.
Collapse
Affiliation(s)
- J R Crosby
- Department of Pathology, University of Washington, Seattle, Washington, USA
| | | | | | | |
Collapse
|
27
|
Abstract
As the number of mouse mutants generated by gene targeting continues to grow exponentially, the challenge is not how to generate a mutant but how to analyse the phenotype. Genes might play multiple roles in development and act in cell-autonomous and cell non-autonomous modes, making phenotypic analysis complex. Genetic mosaic analysis is a powerful tool for dissecting complex gene functions. Classical preimplantation chimeras made between mutant and wild-type embryos can answer many questions, and new genetic techniques for generating restricted genetic mosaicism promise to enhance the future power of mosaic analysis in mammals.
Collapse
Affiliation(s)
- J Rossant
- Department of Medical Genetics and Microbiology, University of Toronto, Ontario, Canada.
| | | |
Collapse
|
28
|
Crosby JR, Seifert RA, Soriano P, Bowen-Pope DF. Chimaeric analysis reveals role of Pdgf receptors in all muscle lineages. Nat Genet 1998; 18:385-8. [PMID: 9537425 DOI: 10.1038/ng0498-385] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Blood vessels originate as simple endothelial cell tubes. It has been proposed that platelet-derived growth factor B polypeptide (Pdgfb) secreted by these endothelial cells drives the formation of the surrounding muscular wall by recruiting nearby mesenchymal cells. However, targetted inactivation of the Pdgfb gene or the Pdgf receptor beta (Pdgfrb) gene, by homologous recombination, does not prevent the development of apparently normal large arteries and connective tissue. We have used an in vivo competition assay in which we prepared chimaeric blastocysts, composed of a mixture of wild-type (Pdgfrb[+/+]) and Pdgfrb(+/-) or wild-type and Pdgfrb(-/-) cells, and quantified the relative success of cells of the two component genotypes in competing for representation in different cell lineages as the chimaeric embryos developed. This study revealed that the participation of Pdgfrb(-/-) cells in all muscle lineages (smooth, cardiac, skeletal and pericyte) was reduced by eightfold compared with Pdgfrb(+/+) cells, and that participation of Pdgfrb(+/-) cells was reduced by twofold (eightfold for pericytes). Pdgfrb inactivation did not affect cell contribution to non-muscle mesodermal lineages, including fibroblasts and endothelial cells. Chimaera competition is therefore a sensitive, quantitative method for determining developmental roles of specific genes, even when those roles are not apparent from analysis of purebred mutants; most likely because they are masked by homeostatic mechanisms.
Collapse
Affiliation(s)
- J R Crosby
- Department of Pathology, University of Washington, Seattle 98195-7470, USA
| | | | | | | |
Collapse
|
29
|
Hamre KM, Goldowitz D. meander tail acts intrinsic to granule cell precursors to disrupt cerebellar development: analysis of meander tail chimeric mice. Development 1997; 124:4201-12. [PMID: 9334269 DOI: 10.1242/dev.124.21.4201] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The murine mutation meander tail (gene symbol: mea) causes a near-total depletion of granule cells in the anterior lobe of the cerebellum, as well as aberrantly located Purkinje cells with misoriented dendrites and radial glia with stunted processes. Whether one, two or all three of these cell types is the primary cellular target(s) of the mutant gene is unknown. This issue is addressed by examining cerebella from adult chimeras in which both the genotype and phenotype of individual cells are marked and examined. From this analysis, three novel observations are made. First, genotypically mea/mea Purkinje cells and glial cells exhibit normal morphologies in the cerebella of chimeric mice indicating that the mea gene acts extrinsically to these two cell populations. Second, few genotypically mea/mea granule cells are present in the anterior lobe or, unexpectedly, in the posterior lobe. These findings indicate that the mea gene acts intrinsically to the granule cell or its precursors to perturb their development. Third, there are near-normal numbers of cerebellar granule cells in the chimeric cerebellum. This result suggests that mea/mea cells are out-competed and subsequently replaced by an increased cohort of wild-type granule cells resulting from an upregulation of wild-type granule cells in the chimeric environment. We propose that the wild-type allele of the mea gene is critical for the developmental progression of the early granule cell neuroblast.
Collapse
Affiliation(s)
- K M Hamre
- Department of Anatomy and Neurobiology, University of Tennessee, Memphis, 38163, USA.
| | | |
Collapse
|
30
|
West JD, Hodson BA, Keighren MA. Quantitative and spatial information on the composition of chimaeric fetal mouse eyes from single histological sections. Dev Growth Differ 1997; 39:305-17. [PMID: 9227897 DOI: 10.1046/j.1440-169x.1997.t01-2-00006.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The spatial distribution of cells in chimaeric tissues, composed of two genotypes, provides insights into the extent of cell mixing during development and growth. However, direct measurement of patch sizes is not usually meaningful because, when the proportion of one genotype is high, a single patch may encompass several adjacent coherent clones of like genotype (clone aggregation). Two previously used methods of comparing patch lengths were evaluated to overcome this problem. The corrected mean patch length (corrected for the predicted effects of random clone aggregation) is a more useful summary statistic than the median patch length of the minor genotype, because its use is not restricted to grossly unbalanced chimaeras, but its validity has been questioned. The two methods gave almost identical numerical summaries of patch sizes in the retinal pigment epithelium of fetal chimaeras, thereby validating the use of the corrected mean patch length for this tissue. The present study also showed that the corrected patch length was unaffected by the presence of cells hemizygous for the TgN(Hbb-b1)83Clo transgene and that the proportion of pigmented cells in a single histological section was representative of the overall composition of the chimaeric fetus.
Collapse
Affiliation(s)
- J D West
- Department of Obstetrics and Gynaecology, University of Edinburgh, UK
| | | | | |
Collapse
|
31
|
West JD, Keighren MA, Flockhart JH. A quantitative test for developmental neutrality of a transgenic lineage marker in mouse chimaeras. Genet Res (Camb) 1996; 67:135-46. [PMID: 8801186 DOI: 10.1017/s0016672300033590] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
The mouse transgene, provisionally designated TgN(Hbb-b1)83Clo, was produced by Dr C. Lo by pronuclear injection of the cloned beta-major globin gene and comprises a highly reiterated sequence that is readily detected by DNA in situ hybridization on histological sections. This fulfils many of the requirements of an ideal genetic cell marker and has been widely used for lineage studies with mouse chimaeras. However, it is not known whether it causes cell selection or influences developmental processes, such as cell mixing, in chimaeric tissues. In the present study, non-transgenic genetic markers (electrophoretic polymorphisms of glucose phosphate isomerase and differences in eye pigmentation) revealed no significant effect of the presence of hemizygous transgenic cells on the overall composition, size or gross morphology of 12 1/2 d chimaeric foetuses, placentas or extraembryonic membranes. Also, a previously described maternal genetic effect on the composition of chimaeric tissues occurred in the presence or absence of the transgene. These tests have demonstrated that hemizygous cells are not at a significant selective disadvantage, when incorporated into mouse aggregation chimaeras with non-transgenic cells. Further studies are needed to test whether homozygous transgenic cells are also selectively neutral and to test whether hemizygous or homozygous transgenic cells influence developmental processes, such as cell mixing, that were not tested.
Collapse
Affiliation(s)
- J D West
- Department of Obstetrics and Gynaecology, University of Edinburgh, UK
| | | | | |
Collapse
|
32
|
Abstract
Mouse embryos, homozygous for the small eye (Sey) mutation die soon after birth with severe facial abnormalities that result from the failure of the eyes and nasal cavities to develop. Mutations in the Pax6 gene are responsible for the Sey phenotype. As a general disruption of eye and nasal development occurs in the homozygous Sey embryos, it is unclear, from the mutant phenotype alone, which tissues require functional Psx6. To examine the roles for Pax6 in eye and nasal development we produced chimeric mouse embryos composed of wild-type and Sey mutant cells. In these embryos we found that mutant cells were excluded from both the lens and nasal epithelium. Both of these tissues were smaller, and in some cases absent, in chimeras with high proportions of mutant cells. The morphology of the optic cup was also severely affected in these chimeras; mutant cells were excluded from the retinal pigmented epithelium and did not intermix with wild-type cells in other regions. The evidence shows that Pax6 has distinct roles in the nasal epithelium and the principal tissue components of the embryonic eye, acting directly and cell autonomously in the optic cup and lens. We suggest that Pax6 may promote cell surface changes in the optic cup and control the fate of the ectoderm from which the lens and nasal epithelia are derived.
Collapse
Affiliation(s)
- J C Quinn
- Department of Obstetrics and Gynecology, University of Edinburgh, UK
| | | | | |
Collapse
|
33
|
Goldowitz D, Rice DS, Williams RW. Clonal architecture of the mouse retina. PROGRESS IN BRAIN RESEARCH 1996; 108:3-15. [PMID: 8979790 DOI: 10.1016/s0079-6123(08)62528-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The study of chimeric retinas has yielded insight on the early development of retina. The close match in chimerism ratios between right and left retinas is significant and supports the idea that both retinas originate from a common population of progenitors. We are able to estimate numbers of progenitor cells that contribute to the formation of the retina and the approximate time at which this small group is isolated from surrounding prosencephalic cell fields. These cells undergo at least five rounds of division before the first retinal neurons are generated. The mouse retina is not build from the center outward. There is simultaneous expansion and differentiation in all parts of the retina and as a result clones are not arranged in wedges. Instead the mouse retina is a patchwork of clones that do not differ greatly in size from center to periphery. The most consistent radial feature in mouse retina is a raphe left at the line of fusion of the margins of the ventral fissure. Processes that shape the clonal patchwork are both passive and active, intrinsic and extrinsic. Certain features of the clonal architecture of the retina, such as the size differences of clones are primarily passive responses to extrinsic forces on progenitor cells and their progeny. The fifteen-fold range in the size of cohorts is not due to intrinsic differences in the proliferative capacity of individual progenitor cells, but is due to the extent of cell movement and mixing at early stages of development. In contrast, active or intrinsic processes are illustrated by the partial (and still controversial) restriction of retinal progenitors, the possible clonal differences between ganglion cells with crossed and uncrossed projections, and the consistent differences in ratios of albino and pigmented genotypes in peripheral and central retina.
Collapse
Affiliation(s)
- D Goldowitz
- Center for Neuroscience, University of Tennessee, Memphis 38163, USA
| | | | | |
Collapse
|
34
|
Distribution of androgenetic cells in fetal mouse chimeras. ACTA ACUST UNITED AC 1995; 204:484-493. [DOI: 10.1007/bf00360856] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/1995] [Accepted: 04/26/1995] [Indexed: 10/26/2022]
|
35
|
Ioffe E, Liu Y, Bhaumik M, Poirier F, Factor SM, Stanley P. WW6: an embryonic stem cell line with an inert genetic marker that can be traced in chimeras. Proc Natl Acad Sci U S A 1995; 92:7357-61. [PMID: 7638196 PMCID: PMC41338 DOI: 10.1073/pnas.92.16.7357] [Citation(s) in RCA: 64] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
Mutant mice produced by gene targeting in embryonic stem (ES) cells often have a complex or embryonic lethal phenotype. In these cases, it would be helpful to identify tissues and cell types first affected in mutant embryos by following the contribution to chimeras of ES cells homozygous for the mutant allele. Although a number of strategies for following ES cell development in vivo have been reported, each has limitations that preclude its general application. In this paper, we describe ES cell lines that can be tracked to every nucleated cell type in chimeras at all developmental stages. These lines were derived from blastocysts of mice that carry an 11-Mb beta-globin transgene on chromosome 3. The transgene is readily detected by DNA in situ hybridization, providing an inert, nuclear-localized marker whose presence is not affected by transcriptional or translational controls. The "WW" series of ES lines possess the essential features of previously described ES lines, including giving rise to a preponderance of male chimeras, all of which have to date exhibited germ-line transmission. In addition, clones selected for single or double targeting events form strong chimeras, demonstrating the feasibility of using WW6 cells to identify phenotypes associated with the creation of a null mutant.
Collapse
Affiliation(s)
- E Ioffe
- Department of Cell Biology, Albert Einstein College of Medicine, Bronx, NY 10461, USA
| | | | | | | | | | | |
Collapse
|
36
|
Fundele R, Herzfeld A, Li LL, Barton SC, Surani MA. Proliferation and differentiation of androgenetic cells in fetal mouse chimeras. ACTA ACUST UNITED AC 1995; 204:494-501. [DOI: 10.1007/bf00360857] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/1995] [Accepted: 05/11/1995] [Indexed: 10/26/2022]
|
37
|
Tissue specific loss of proliferative capacity of parthenogenetic cells in fetal mouse chimeras. ACTA ACUST UNITED AC 1995; 204:436-443. [PMID: 28305863 DOI: 10.1007/bf00360851] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/1994] [Accepted: 01/05/1995] [Indexed: 10/26/2022]
Abstract
Parthenogenetic cells are lost from fetal chimeras. This may be due to decreased proliferative potential. To address this question, we have made use of combined cell lineage and cell proliferation analysis. Thus, the incorporation of bromodeoxyuridine in S-phase was determined for both parthenogenetic and normal cells in several tissues of fetal day 13 and 17 chimeras. A pronounced reduction of bromodesoxyuridine incorporation by parthenogenetic cells at both developmental stages was only observed in cartilage. In brain, skeletal muscle, heart and intestinal epithelium, this reduction was either less pronounced or observed only at one of the developmental stages analysed. No difference between parthenogenetic and normal cells was observed in epidermis and ganglia. Our results show that a loss of proliferative potential of parthenogenetic cells during fetal development contributes to their rapid elimination in some tissues. The analysis of the fate of parthenogenetic cells in skeletal muscle and cartilage development demonstrated different selection mechanisms in these tissues. In skeletal muscle, parthenogenetic cells were largely excluded from the myogenic lineage proper by early post-midgestation. In primary hyaline cartilage, parthenogenetic cells persisted into adulthood but were lost from cartilages that undergo ossification during late fetal development.
Collapse
|
38
|
Heng HH, Tsui LC, Moens PB. Organization of heterologous DNA inserts on the mouse meiotic chromosome core. Chromosoma 1994; 103:401-7. [PMID: 7859560 DOI: 10.1007/bf00362284] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
With simultaneous immunofluorescence and fluorescent in situ hybridization, we have determined the organization of native and heterologous DNA sequences relative to the cores of meiotic prophase chromosomes. The normal chromatin organization is demonstrated with probes of mouse sequences: a cosmid probe that identifies unique sequences and a 720 kb yeast artificial chromosome (YAC) probe that recognizes a specific region of the chromatin domain. The heterologous DNA consists of a 1.8 Mb insertion of 40 tandem head-to-tail phage lambda LIZ vectors and of 11.4 Mb of bacterial/mouse DNA repeats. The lengthy lambda insert is unusual in that it is not contained in the chromatin domain of chromosome 4 and in that it fails to form direct attachments to the chromosome core. The ends are attached indirectly, probably by means of the flanking mouse sequences. At late stages of meiotic prophase, while the terminal attachments remain the same, the lambda DNA becomes highly compacted. Apparently, higher order condensation and core attachment are independent processes. The condensed inserts relax precociously at metaphase I. In the mouse heterozygous for the insert, the two sister inserts are usually merged, as are all four inserts in the homozygous mouse. Evidently chromatin loops with identical sequences can become associated during meiotic prophase. Mouse sequences within a heterologous DNA insert (repeats of bacterial plasmid pBR322 with a mouse beta-globin insert) were observed to restore some degree of core attachment.
Collapse
Affiliation(s)
- H H Heng
- Department of Molecular and Medical Genetics, University of Toronto, Ontario, Canada
| | | | | |
Collapse
|
39
|
Ewart JL, Richa J, Lo CW. Widespread distribution of cells containing human DNA in embryos derived from mouse eggs injected with human chromosome fragments. Hum Gene Ther 1993; 4:597-607. [PMID: 8280798 DOI: 10.1089/hum.1993.4.5-597] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The possibility that metaphase chromosomes can serve as a source of genetic material for making transgenic mice was suggested by our previous finding of the incorporation of human satellite DNA into mouse embryos that were injected with microdissected human centromeric fragments. In the present study, we further examined whether this chromosome transfer method can be used to generate transgenic mice containing a portion of human chromosome 4 spanning the Huntington's disease (HD) gene. For this purpose, we used an improved method of metaphase chromosome preparation that may minimize the potential for DNA damage. Using metaphase chromosomes prepared in this manner, chromosome fragments spanning the region of chromosome 4 containing the HD gene were microdissected, retrieved, and injected into fertilized mouse eggs. The injected eggs exhibited good viability and developed with a high efficiency when implanted into foster mothers. To determine whether the human DNA from the injected chromosome fragment had been incorporated into the mouse genome, embryos were harvested at 12.5 days of gestation (dg) and analyzed by in situ hybridization using a human Alu repetitive DNA probe. This analysis showed that most of the embryos contained cells with human Alu repeats. However, all of the embryos were mosaic, and the level of mosaicism was such that we were not able to determine the precise chromosomal origin of the human DNA insert. We discuss the possible basis for the mosaicism and the potential value of such mosaic animals for studying Huntington's disease.
Collapse
Affiliation(s)
- J L Ewart
- Department of Biology, University of Pennsylvania, Goddard Laboratories, Philadelphia 19104-6017
| | | | | |
Collapse
|
40
|
Jägerbauer EM, Fraser A, Herbst EW, Kothary R, Fundele R. Parthenogenetic stem cells in postnatal mouse chimeras. Development 1992; 116:95-102. [PMID: 1483398 DOI: 10.1242/dev.116.1.95] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The ability of parthenogenetic (pg) cells to contribute to proliferating stem cell populations of postnatal aggregation chimeras was investigated. Using DNA in situ analysis, pg participation was observed in highly regenerative epithelia of various regions of the gastrointestinal tract, e.g., stomach, duodenum and colon, in the epithelia of tongue and uterus and in the epidermis. Pg cells also contributed to the epithelium of the urinary bladder, which is characterized by a relatively slow cellular turnover. Using a sensitive proliferation marker to determine division rate of pg and normal (wt) cells in tissues of a 24-day-old chimera, no significant differences between pg and fertilized cells were observed. However, in colon and uterus of a pg <==> wt chimera aged 101 days, a significant loss of proliferative capacity of pg cells was found. In the colon, this loss of proliferative potential was accompanied by an altered morphology of pg crypts. In general, they were situated at the periphery of the epithelium and lacked access to the lumen, with consequent cystic enlargement and flattened epithelium. No obvious morphological changes were observed in the pg-derived areas of the uterine epithelium of this chimera. Our results provide evidence that pg cells can persist as proliferating stem cells in various tissues of early postnatal chimeras. They suggest that pg-derived stem cells may cease to proliferate in restricted areas of the gastrointestinal tract and in the uterine epithelium of pg <==> wt chimeras of advanced age.(ABSTRACT TRUNCATED AT 250 WORDS)
Collapse
Affiliation(s)
- E M Jägerbauer
- Institut für Biologie III, Universität Freiburg, Germany
| | | | | | | | | |
Collapse
|
41
|
Nakatsuji N, Kadokawa Y, Suemori H. Radial Columnar Patches in the Chimeric Cerebral Cortex Visualized by Use of Mouse Embryonic Stem Cells Expressing beta-Galactosidase. (mouse chimera/ES cell/cerebral cortex/beta-galactosidase). Dev Growth Differ 1991. [DOI: 10.1111/j.1440-169x.1991.00571.x] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
|
42
|
Heterochromatic features of an 11-megabase transgene in brain cells. Proc Natl Acad Sci U S A 1991; 88:1049-53. [PMID: 1992455 PMCID: PMC50952 DOI: 10.1073/pnas.88.3.1049] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Transgenic mice provide a remarkable experimental setting for the study of nuclear architecture. The three-dimensional localization and fine structure of a foreign DNA within the mouse genome can be conveniently followed by using high-resolution in situ hybridization. Foreign DNAs designed with specific characteristics, such as base bias, sequence motif(s), and size can stably integrate into finite positions on host chromosomes. Thus the relative importance of each of these characteristics in determining the three-dimensional nuclear position and the detailed morphology of the transgene can be evaluated in different cell types. The aim of this study was to evaluate a transgene with sequence characteristics that might contribute to the de novo formation of heterochromatin in interphase nuclei. The structure of a phenotypically silent 11-megabase transgene, containing tandem repeats of beta-globin-pBR sequences integrated into the peritelomeric region of both mouse chromosome 3 homologs, was determined in adult brain cells. Neurons that are largely euchromatic were especially informative in three-dimensional studies of transgene position. The two transgenic loci behaved much like centromeric or paracentromeric A + T-rich satellite DNAs of comparable length from a single chromosome; one or both transgene domains localized together with centromeric satellite DNA on the nucleolus. This is an unusual nuclear position for a telomeric or chromosome arm region that does not contain a substantial amount of constitutively heterochromatic satellite DNA. G + C richness did not prevent these regions from assembling as dense heterochromatic bodies of approximately 1 micron3 in volume. Ultrastructurally, transgenic domains were often intimately connected with constitutive heterochromatin and were highly condensed. Labeled supercoils, formed by a discrete approximately 250-nm-wide fiber, were observed in oblique thin sections through the center of the domain. The structural data were consistent with negligible transcriptional activity detected for this locus, as well as the predicted conformation of constitutive heterochromatin. Interestingly, in transgenic but not control mice, a substantial number of large neurons, including approximately 30% of cerebellar Purkinje cells, showed excessive invaginations of the nuclear membrane.
Collapse
|
43
|
Abstract
Metaphase chromosomes are dynamically modified in interphase. This review focuses on how these structures can be modified, and explores the functional mechanisms and significance of these changes. Current analyses of genes often focus on relatively short stretches of DNA and consider chromatin conformations that incorporate only a few kilobases of DNA. In interphase nuclei, however, orderly transcription and replication can involve highly folded chromosomal domains containing hundreds of kilobases of DNA. Specific "junk" DNA sequences within selected chromosome domains may participate in more complex levels of chromosome folding, and may index different genetic compartments for orderly transcription and replication. Three-dimensional chromosome positions within the nucleus may also contribute to phenotypic expression. Entire chromosomes are maintained as discrete, reasonably compact entities in the nucleus, and heterochromatic coiled domains of several thousand kilobases can acquire unique three-dimensional positions in differentiated cell types. Some aspects of neoplasia may relate to alterations in chromosome structure at several higher levels of organization.
Collapse
|
44
|
Affiliation(s)
- J Rossant
- Division of Molecular and Developmental Biology, Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada
| |
Collapse
|
45
|
Goldowitz D. Cell allocation in mammalian CNS formation: evidence from murine interspecies aggregation chimeras. Neuron 1989; 3:705-13. [PMID: 2642015 DOI: 10.1016/0896-6273(89)90239-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The central nervous system of murine intraspecies chimeras generally consists of an apparently random mixture of neurons derived from each of the parental genotypes. In this study, interspecies mouse chimeras were examined, and an analysis of the parental genotype donation to the chimeric CNS revealed large clusters of like-genotype neurons in small regions as well as in major subdivisions of the CNS. This coherent clustering of like-genotype neurons is proposed to be due to an autonomous developmental clock that is sufficiently mismatched between species to create preferential cell allotment in the chimeric brain.
Collapse
Affiliation(s)
- D Goldowitz
- Department of Anatomy and Neurobiology, University of Tennessee Health Science Center, Memphis 38163
| |
Collapse
|
46
|
KATOH KAZUTO, YOKOYAMA MINESUKE, KIMURA SHIARI, HIRAMOTO YUKIO, KONDOH HISATO. Analysis of Cellular Mosaicism in a Transgenic Mouse by Histological In Situ Hybridization. (Transgenic mice/mosaics/cell lineage/in situ hybridization). Dev Growth Differ 1988. [DOI: 10.1111/j.1440-169x.1988.00639.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|