1
|
Kerns JL, Steward R, Corbetta-Rastelli C, Pearlson GA, Sokoloff A, Bednarek PH, Drey EA. Intrafetal digoxin as an adjuvant for dilation and evacuation at 20 to 24 weeks’ gestation: a randomized, double-blind, placebo-controlled trial. Contraception 2019. [DOI: 10.1016/j.contraception.2019.03.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
2
|
Fuller L, Whitford H, Cristiano Y, Robinson R, Steward R, Poulsen M, Shi W, Snell G. What Happens to Frailty in the First Year after Lung Transplantation? J Heart Lung Transplant 2019. [DOI: 10.1016/j.healun.2019.01.478] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
|
3
|
Joy K, Natavio M, Steward R, Opper N, Silverstein E, Goldsmith C, Sech L, Mishell D. Patient preferences regarding the use of nonhormonal contraceptive methods. Contraception 2014. [DOI: 10.1016/j.contraception.2014.05.111] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
4
|
Tarrant B, Martin R, Steward R, Snell G, Westall G. Physical Outcomes Post Paediatric Lung Transplant - Implications of Extra-Corporeal Membrane Oxygenation (ECMO). J Heart Lung Transplant 2014. [DOI: 10.1016/j.healun.2014.01.335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
|
5
|
Peavey M, Steward R, Paulyson-Nunez K, James A. Successful prophylactic regimens for transvaginal oocyte retrieval in women with bleeding diatheses. Haemophilia 2013; 19:e189-91. [PMID: 23600910 DOI: 10.1111/hae.12135] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/03/2013] [Indexed: 11/30/2022]
|
6
|
Gualtieri M, Steward R, Wilson M, Paulson R, Mishell D. Defining dose-response of copper surface area on sperm motility. An evaluation of the copper contained in the copper intrauterine device (Cu-IUD). Fertil Steril 2013. [DOI: 10.1016/j.fertnstert.2013.07.1842] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
7
|
Fels H, Steward R, Melamed A, Granat A, Stanczyk F, Mishell D. Comparison of hormone levels in cervical mucus and serum of 24/4 versus 21/7 combined oral contraceptives. Contraception 2012. [DOI: 10.1016/j.contraception.2012.05.107] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
|
8
|
Steward R, Goldsberry S, Hernandez A, Melamed A, Segall-Gutierrez P, Heger A. Incidence of pregnancy after use of emergency contraception in sexually assaulted women. Contraception 2012. [DOI: 10.1016/j.contraception.2011.11.062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
|
9
|
Steward R, Gatter M, Nucatola D. The safety of digoxin as a feticidal agent. Contraception 2010. [DOI: 10.1016/j.contraception.2010.04.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
10
|
Abstract
The nuclear factor kappa B (NF-kappaB) pathways in Drosophila are multi-component pathways, as in vertebrates, that regulate the expression of many genes responsible for the formation of dorsal-ventral polarity in the early embryo, the innate immune response to infection with Gram- negative and positive bacteria and fungi, the cellular immune response and hematopoiesis. Overactivation of the fly pathway can result in developmental defects, overproliferation of hemocytes and the formation of melanotic tumors or nodules. The extracellular events leading to the maturation of the ligand for initiation of the Drosophila NF-kappaB pathway is not conserved between flies and vertebrates, but the Toll receptor and downstream events are remarkably similar. NF-kappaB proteins have been identified in mollusks, and arthropods such as horseshoe crabs and beetles, indicating that this pathway has been established more than 500 million years ago. The fly NF-kappaB pathways are less complex than those in vertebrates, with the involvement of fewer proteins, but they are, nonetheless, just as important as their vertebrate counterparts for the life of the fly.
Collapse
Affiliation(s)
- S Minakhina
- Waksman Institute, Department of Molecular Biology and Biochemistry and the Cancer Institute of New Jersey, Rutgers University, Piscataway, NJ 08854, USA
| | | |
Collapse
|
11
|
Affiliation(s)
- S Govind
- Shubha Govind and Ruth Steward, Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, USA
| | | |
Collapse
|
12
|
Reinberg D, Chuikov S, Farnham P, Karachentsev D, Kirmizis A, Kuzmichev A, Margueron R, Nishioka K, Preissner TS, Sarma K, Abate-Shen C, Steward R, Vaquero A. Steps toward understanding the inheritance of repressive methyl-lysine marks in histones. Cold Spring Harb Symp Quant Biol 2004; 69:171-82. [PMID: 16117647 DOI: 10.1101/sqb.2004.69.171] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Affiliation(s)
- D Reinberg
- Howard Hughes Medical Institute, Division of Nucleic Acids Enzymology, Department of Biochemistry, Robert Wood Johnson Medical School, Piscataway, New Jersey 08854, USA
| | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
13
|
Abstract
Bicaudal-D (Bic-D) is required for the transport of determinant mRNAs and proteins to the presumptive oocyte, an essential step in the differentiation of the oocyte. Bic-D protein contains four well-defined heptad repeat domains characteristic of intermediate filament proteins. We characterized the ovarian phenotypes of females expressing mutant Bic-D proteins (Bic-D(H)) deleted for each of the heptad repeat domains. The altered migration of follicle cells we observe in mutant ovaries suggests that Bic-D functions in the germline and directs the inward migration of somatic follicle cells. In the germarium Bic-D is required for the organization of the egg chamber and the structural integrity of the oocyte and nurse cells. Examination of the polarized microtubule network in Bic-D(H) ovaries shows that Bic-D function is required for both the establishment of the polarized microtubule network and its maintenance throughout oogenesis. To explain the multiple functions suggested by the pleiotropic Bic-D phenotype, we propose that Bic-D protein could form itself a filamentous structure and represent an integral, essential part of the cytoskeleton.
Collapse
Affiliation(s)
- J Oh
- Waksman Institute, Department of Molecular Biology and Biochemistry, Rutgers University, 190 Frelinghuysen Road, Piscataway, New Jersey, 08854, USA
| | | |
Collapse
|
14
|
Steward R, Richards M, Brayne C. Highlights of Papers in Clinical Investigations Section: Vascular Risk and Cognitive Impairment in an Older, British, African‐Caribbean Population. J Am Geriatr Soc 2001. [DOI: 10.1046/j.1532-5415.2001.49302453.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
15
|
Lumsden MA, Andrews F, Steward R. Access to undergraduate medical education is being broadened. BMJ 2001; 322:495. [PMID: 11256370 PMCID: PMC1119699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/19/2023]
|
16
|
Abstract
Haplo-insufficiency of human Lis1 causes lissencephaly. Reduced Lis1 activity in both humans and mice results in a neuronal migration defect. Here we show that Drosophila Lis1 is highly expressed in the nervous system. Lis1 is essential for neuroblast proliferation and axonal transport, as shown by a mosaic analysis using a Lis1 null mutation. Moreover, it is cell-autonomously required for dendritic growth, branching and maturation. Analogous mosaic analysis shows that neurons containing a mutated cytoplasmic-dynein heavy chain (Dhc64C) exhibit phenotypes similar to Lis1 mutants. These results implicate Lis1 as a regulator of the microtubule cytoskeleton and show that it is important for diverse physiological functions in the nervous system.
Collapse
Affiliation(s)
- Z Liu
- Department of Biological Sciences, Stanford University, Stanford, California 94305-5020, USA
| | | | | |
Collapse
|
17
|
Munn K, Steward R. The shut-down gene of Drosophila melanogaster encodes a novel FK506-binding protein essential for the formation of germline cysts during oogenesis. Genetics 2000; 156:245-56. [PMID: 10978289 PMCID: PMC1461232 DOI: 10.1093/genetics/156.1.245] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
In Drosophila melanogaster, the process of oogenesis is initiated with the asymmetric division of a germline stem cell. This division results in the self-renewal of the stem cell and the generation of a daughter cell that undergoes four successive mitotic divisions to produce a germline cyst of 16 cells. Here, we show that shut-down is essential for the normal function of the germline stem cells. Analysis of weak loss-of-function alleles confirms that shut-down is also required at later stages of oogenesis. Clonal analysis indicates that shut-down functions autonomously in the germline. Using a positional cloning approach, we have isolated the shut-down gene. Consistent with its function, the RNA and protein are strongly expressed in the germline stem cells and in 16-cell cysts. The RNA is also present in the germ cells throughout embryogenesis. shut-down encodes a novel Drosophila protein similar to the heat-shock protein-binding immunophilins. Like immunophilins, Shut-down contains an FK506-binding protein domain and a tetratricopeptide repeat. In plants, high-molecular-weight immunophilins have been shown to regulate cell divisions in the root meristem in response to extracellular signals. Our results suggest that shut-down may regulate germ cell divisions in the germarium.
Collapse
Affiliation(s)
- K Munn
- Waksman Institute, Rutgers University, Piscataway, New Jersey 08854, USA
| | | |
Collapse
|
18
|
Abstract
Rel transcription factors function in flies and vertebrates in immunity and development. Although Rel proteins regulate diverse processes, the control of their function is conserved. In a two-hybrid screen for additional components of the pathway using the Drosophila I-kappaB protein Cactus as a bait, we isolated a novel coiled-coil protein with N-terminal Arg-Asp (RD)- like motifs that we call Cactin. Like the other components of this pathway, Cactin is evolutionarily conserved. Over-expression of cactin in a cactus(A2) heterozygous background results in the enhancement of the cactus phenotype. Both the embryonic lethality and ventralization are strongly increased, suggesting that cactin functions in the Rel pathway controlling the formation of dorsal-ventral embryonic polarity.
Collapse
Affiliation(s)
- P Lin
- Waksman Institute, Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway,NJ 08854-8020, USA
| | | | | |
Collapse
|
19
|
Fernandez R, Takahashi F, Liu Z, Steward R, Stein D, Stanley ER. The Drosophila shark tyrosine kinase is required for embryonic dorsal closure. Genes Dev 2000; 14:604-14. [PMID: 10716948 PMCID: PMC316420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
Dorsal closure (DC) in the Drosophila embryo requires the coordinated interaction of two different functional domains of the epidermal cell layer-the leading edge (LE) and the lateral epidermis. In response to activation of a conserved c-Jun amino-terminal kinase (JNK) signaling module, the dorsal-most layer of cells, which constitute the LE of the stretching epithelial sheet, secrete Dpp, a member of the TGFbeta superfamily. Dpp and other LE cell-derived signaling molecules stimulate the bilateral dorsal elongation of cells of the dorsolateral epidermis over the underlaying amnioserosa and the eventual fusion of their LEs along the dorsal midline. We have found that flies bearing a Shark tyrosine kinase gene mutation, shark(1), exhibit a DC-defective phenotype. Dpp fails to be expressed in shark(1) mutant LE cells. Consistent with these observations, epidermal-specific reconstitution of shark function or overexpression of an activated form of c-Jun in the shark(1) mutant background, rescues the DC defect. Thus, Shark regulates the JNK signaling pathway leading to Dpp expression in LE cells. Furthermore, constitutive activation of the Dpp pathway throughout the epidermis fails to rescue the shark(1) DC defect, suggesting that Shark may function in additional pathways in the LE and/or lateral epithelium.
Collapse
Affiliation(s)
- R Fernandez
- Department of Developmental and Molecular Biology, Albert Einstein College of Medicine, The Bronx, New York 10461, USA
| | | | | | | | | | | |
Collapse
|
20
|
Abstract
The localization of oocyte-specific determinants in the form of mRNAs to the pro-oocyte is essential for the establishment of oocyte identity. Localization of the Bicaudal-D (Bic-D) protein to the presumptive oocyte is required for the accumulation of Bic-D and other mRNAs to the pro-oocyte. The Bic-D protein contains four well-defined heptad repeat domains characteristic of intermediate filament proteins, and several of the mutations in Bic-D map to these conserved domains. We have undertaken a structure-function analysis of Bic-D by testing the function of mutant Bic-D transgenes (Bic-D(H)) deleted for each of the heptad repeat domains in a Bic-D null background. Our transgenic studies indicate that only the C-terminal heptad repeat deletion results in a protein that has lost zygotic and ovarian functions. The three other deletions result in proteins with full zygotic function, but with affected ovarian function. The functional importance of each domain is well correlated with its conservation in evolution. The analysis of females heterozygous for Bic-D(H) and the existing alleles Bic-D(PA66) or Bic-D(R26) reveals that Bic-D(R26) as well as some of Bic-D(H) transgenes have antimorphic effects. The yeast two-hybrid interaction assay shows that Bic-D forms homodimers. Furthermore, we found that Bic-D exists as a multimeric protein complex consisting of Egl and at least two Bic-D monomers.
Collapse
Affiliation(s)
- J Oh
- Waksman Institute of Microbiology, Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, New Jersey 08854-8020, USA
| | | | | |
Collapse
|
21
|
Abstract
Rel-family transcription factors function in a variety of biological processes, including development and immunity. During early Drosophila development, the Toll-Cactus-Dorsal pathway regulates the establishment of the embryonic dorsoventral axis. The last step in this pathway is the graded nuclear import of the Rel protein Dorsal. Dorsal is retained in the cytoplasm by the IkappaB-family protein Cactus. Phosphorylation of both Dorsal and Cactus is regulated by a Toll-receptor-dependent ventral signal relayed by the Tube and Pelle proteins. Phosphorylation of Cactus leads to its degradation and to the release of Dorsal to form a ventral-to-dorsal nuclear Dorsal gradient. To understand how the ventral signal regulates the nuclear import and activity of Dorsal, we deleted its conserved nuclear localization signal (NLS). The truncated protein remained in the cytoplasm and could antagonize the function of wild-type Dorsal, suggesting that Dorsal forms a dimer in the cytoplasm. Further, the nuclear import of a mutant Dorsal protein that failed to interact with Cactus was still regulated by the ventral signal. Our results are consistent with a model in which ventral signal-dependent modification of both Cactus and Dorsal is required for the graded nuclear import of Dorsal.
Collapse
Affiliation(s)
- E A Drier
- Waksman Institute, Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, New Jersey 08854-8020, USA
| | | | | |
Collapse
|
22
|
Bhattacharya A, Sudha S, Chandra HS, Steward R. flex, an X-linked female-lethal mutation in Drosophila melanogaster controls the expression of Sex-lethal. Development 1999; 126:5485-93. [PMID: 10556072 DOI: 10.1242/dev.126.23.5485] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The Sex-lethal (Sxl) gene is required in Drosophila females for sexual differentiation of the soma, for gem cell differentiation and dosage compensation. We have isolated three new alleles of female-lethal-on-X (flex), an X-linked female-lethal mutation and have characterized its function in sex determination. SXL protein is missing in flex/flex embryos, however transcription from both Sxl(Pe), the early Sxl promoter and Sxl(Pm), the late maintenance promoter, is normal in flex homozygotes. In flex/flex embryos, Sxl mRNA is spliced in the male mode. Analysis of flex germline clones shows that it also functions in oogenesis, but in contrast to Sxl mutants that show an early arrest tumorous phenotype, flex mutant egg chambers develop to stage 10. In flex ovarian clones, Sxl RNA is also spliced in the male form. Hence, flex is a sex-specific regulator of Sxl functioning in both the soma and the germline. Genetic interaction studies show that flex does not enhance female lethality of Sxl loss-of-function alleles but it rescues the male-specific lethality of both of the gain-of-function Sxl mutations, Sxl(M1)and Sxl(M4.) In contrast to mutations in splicing regulators of Sxl, the female lethality of flex is not rescued by either Sxl(M1)or Sxl(M4). Based on these observations, we propose that flex regulates Sxl at a post-splicing stage and regulates either its translation or the stability of the SXL protein.
Collapse
Affiliation(s)
- A Bhattacharya
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560 012, India
| | | | | | | |
Collapse
|
23
|
Liu Z, Xie T, Steward R. Lis1, the Drosophila homolog of a human lissencephaly disease gene, is required for germline cell division and oocyte differentiation. Development 1999; 126:4477-88. [PMID: 10498683 DOI: 10.1242/dev.126.20.4477] [Citation(s) in RCA: 100] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Lissencephaly is a severe congenital brain malformation resulting from incomplete neuronal migration. One causal gene, LIS1, is homologous to nudF, a gene required for nuclear migration in A. nidulans. We have characterized the Drosophila homolog of LIS1 (Lis1) and show that Lis1 is essential for fly development. Analysis of ovarian Lis1 mutant clones demonstrates that Lis1 is required in the germline for synchronized germline cell division, fusome integrity and oocyte differentiation. Abnormal packaging of the cysts was observed in Lis1 mutant clones. Our results indicate that LIS1 is important for cell division and differentiation and the function of the membrane cytoskeleton. They support the notion that LIS1 functions with the dynein complex to regulate nuclear migration or cell migration.
Collapse
Affiliation(s)
- Z Liu
- The Waksman Institute, Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, New Jersey 08854-8020, USA
| | | | | |
Collapse
|
24
|
Manfruelli P, Reichhart JM, Steward R, Hoffmann JA, Lemaitre B. A mosaic analysis in Drosophila fat body cells of the control of antimicrobial peptide genes by the Rel proteins Dorsal and DIF. EMBO J 1999; 18:3380-91. [PMID: 10369678 PMCID: PMC1171418 DOI: 10.1093/emboj/18.12.3380] [Citation(s) in RCA: 168] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Expression of the gene encoding the antifungal peptide Drosomycin in Drosophila adults is controlled by the Toll signaling pathway. The Rel proteins Dorsal and DIF (Dorsal-related immunity factor) are possible candidates for the transactivating protein in the Toll pathway that directly regulates the drosomycin gene. We have examined the requirement of Dorsal and DIF for drosomycin expression in larval fat body cells, the predominant immune-responsive tissue, using the yeast site-specific flp/FRT recombination system to generate cell clones homozygous for a deficiency uncovering both the dorsal and the dif genes. Here we show that in the absence of both genes, the immune-inducibility of drosomycin is lost but can be rescued by overexpression of either dorsal or dif under the control of a heat-shock promoter. This result suggests a functional redundancy between both Rel proteins in the control of drosomycin gene expression in the larvae of Drosophila. Interestingly, the gene encoding the antibacterial peptide Diptericin remains fully inducible in the absence of the dorsal and dif genes. Finally, we have used fat body cell clones homozygous for various mutations to show that a linear activation cascade Spaetzle--> Toll-->Cactus-->Dorsal/DIF leads to the induction of the drosomycin gene in larval fat body cells.
Collapse
Affiliation(s)
- P Manfruelli
- Institut de Biologie Moléculaire et Cellulaire, UPR 9022 du Centre National de la Recherche Scientifique, 15, Rue René Descartes, F-67084 Strasbourg Cedex, France
| | | | | | | | | |
Collapse
|
25
|
Abstract
In Drosophila, dorsal-ventral polarity is determined by a maternally encoded signal transduction pathway that culminates in the graded nuclear localization of the Rel protein, Dorsal. Dorsal is retained in the cytoplasm by the IkappaB protein, Cactus. Signal-dependent phosphorylation of Cactus results in the degradation of Cactus and the nuclear targeting of Dorsal. We present an in-depth study of the functional importance of Dorsal phosphorylation. We find that Dorsal is phosphorylated by the ventral signal while associated with Cactus, and that Dorsal phosphorylation is essential for its nuclear import. In vivo phospholabeling of Dorsal is limited to serine residues in both ovaries and early embryos. A protein bearing mutations in six conserved serines abolishes Dorsal activity, is constitutively cytoplasmic, and appears to eliminate Dorsal phosphorylation, but still interacts with Cactus. Two individual serine-to-alanine mutations produce unexpected results. In a wild-type signaling background, a mutation in the highly conserved PKA site (S312) produces only a weak loss-of-function; however, it completely destabilizes the protein in a cactus mutant background. Significantly, the phosphorylation of another completely conserved serine (S317) regulates the high level of nuclear import found in ventral cells. We conclude that the formation of a wild-type Dorsal nuclear gradient requires the phosphorylation of both Cactus and Dorsal. The strong conservation of the serines suggests that phosphorylation of other Rel proteins is essential for their proper nuclear targeting.
Collapse
Affiliation(s)
- E A Drier
- Department of Molecular Biology, Princeton University, Princeton, New Jersey 08544, USA
| | | | | |
Collapse
|
26
|
Abstract
The intracellular part of the Rel signal transduction pathway in Drosophila is encoded by Toll, tube, pelle, dorsal, and cactus, and it functions to form the dorsal-ventral axis in the Drosophila embryo. Upon activation of the transmembrane receptor Toll, Dorsal dissociates from its cytoplasmic inhibitor Cactus and enters the nucleus. Tube and Pelle are required to relay the signal from Toll to the Dorsal-Cactus complex. In a yeast two-hybrid assay, we found that both Tube and Pelle interact with Dorsal. We confirmed these interactions in an in vitro binding assay. Tube interacts with Dorsal via its C-terminal domain, whereas full-length Pelle is required for Dorsal binding. Tube and Pelle bind Dorsal in the N-terminal domain 1 of the Dorsal Rel homology region rather than at the Cactus binding site. Domain 1 has been found to be necessary for Dorsal nuclear targeting. Genetic experiments indicate that Tube-Dorsal interaction is necessary for normal signal transduction. We propose a model in which Tube, Pelle, Cactus, and Dorsal form a multimeric complex that represents an essential aspect of signal transduction.
Collapse
Affiliation(s)
- J Yang
- Waksman Institute and Department of Molecular Biology and Biochemistry, Rutgers University, Piscataway, NJ 08855, USA
| | | |
Collapse
|
27
|
Iwai Y, Usui T, Hirano S, Steward R, Takeichi M, Uemura T. Axon patterning requires DN-cadherin, a novel neuronal adhesion receptor, in the Drosophila embryonic CNS. Neuron 1997; 19:77-89. [PMID: 9247265 DOI: 10.1016/s0896-6273(00)80349-9] [Citation(s) in RCA: 250] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
We identified DN-cadherin, a novel Drosophila cadherin that is expressed in axons and in the mesoderm. Although DN-cadherin has diverged from vertebrate classic cadherins in terms of its extracellular structure, it still can form a complex with catenins and induce cell aggregation, as do the vertebrate molecules. Loss-of-function mutations of the gene resulted in either embryonic lethality or uncoordinated locomotion of adults. In the central nervous system of null mutant embryos, subsets of ipsilateral axons displayed a variety of aberrant trajectories including failure of position shifts, defective bundling, and errors in directional migration of growth cones. These results suggest that processes of axon patterning critically depend on DN-cadherin-mediated axon-axon interactions.
Collapse
Affiliation(s)
- Y Iwai
- Department of Biophysics, Faculty of Science, Kyoto University, Kitashirakawa, Sakyo-ku, Japan
| | | | | | | | | | | |
Collapse
|
28
|
Abstract
Embryonic dorsoventral polarity in Drosophila melanogaster is determined by a maternally-encoded signal transduction pathway whose effector molecule is the Rel transcription factor, Dorsal. The activity of this signal transduction pathway gives rise to a ventral-to-dorsal nuclear gradient of Dorsal, which then activates and represses several zygotic target genes in distinct domains. The dorsoventral system represents the best characterized of the Rel pathways. Its components have now been ordered and their biochemical roles are becoming clearer. Key components of the dorsoventral pathway show striking similarity to those involved with the regulation of vertebrate Rel family members. Additional Drosophila Rel family members have been identified and implicated in the innate immune response. The dorsoventral pathway is also remarkably conserved in this response. This conservation underscores the relevance of the dorsoventral system for our understanding of the entire Rel family.
Collapse
Affiliation(s)
- E A Drier
- Department of Molecular Biology, Princeton University, NJ 08544, USA
| | | |
Collapse
|
29
|
Abstract
The formation of a gradient of nuclear Dorsal protein in the early Drosophila embryo is the last step in a maternally encoded dorsal-ventral signal transduction pathway. This gradient is formed in response to a ventral signal, which leads to the dissociation of cytoplasmic Dorsal from the I kappa B homolog Cactus. Free Dorsal is then targeted to the nucleus. Dorsal is a Rel-family transcription factor. Signal-dependent nuclear localization characterizes the regulation of Rel proteins. In order to identify regions of Dorsal that are essential for its homodimerization, nuclear targeting, and interaction with Cactus, we have performed an in vivo structure-function analysis. Our results show that all these functions are carried out by regions within the conserved Rel-homology region of Dorsal. The C-terminal divergent half of Dorsal is dispensable for its selective nuclear import. A basic stretch of 6 amino acids at the C terminus of the Rel-homology region is necessary for nuclear localization. This nuclear localization signal is not required for Cactus binding. Removal of the N-terminal 40 amino acids abolished the nuclear import of Dorsal, uncovering a potentially novel function for this highly conserved region.
Collapse
Affiliation(s)
- S Govind
- Department of Molecular Biology, Princeton University, New Jersey 08544, USA
| | | | | | | |
Collapse
|
30
|
Abstract
The mechanisms governing anterior-posterior and dorsal-ventral polarity in Drosophila melanogaster had previously been considered as independent processes. However, two papers(1,2) now reveal that both axes are initiated during oogenesis by the same pathway, and also clearly demonstrate that one is dependent on the other.
Collapse
Affiliation(s)
- K Munn
- Waksman Institute, Piscataway, New Jersey 08855-0759, USA
| | | |
Collapse
|
31
|
Lemaitre B, Meister M, Govind S, Georgel P, Steward R, Reichhart JM, Hoffmann JA. Functional analysis and regulation of nuclear import of dorsal during the immune response in Drosophila. EMBO J 1995; 14:536-45. [PMID: 7859742 PMCID: PMC398111 DOI: 10.1002/j.1460-2075.1995.tb07029.x] [Citation(s) in RCA: 184] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
In addition to its function in embryonic development, the NF-kappa B/rel-related gene dorsal (dl) of Drosophila is expressed in larval and adult fat body where its RNA expression is enhanced upon injury. Injury also leads to a rapid nuclear translocation of dl from the cytoplasm in fat body cells. Here we present data which strongly suggest that the nuclear localization of dl during the immune response is controlled by the Toll signaling pathway, comprising gene products that participate in the intracellular part of the embryonic dorsoventral pathway. We also report that in mutants such as Toll or cactus, which exhibit melanotic tumor phenotypes, dl is constitutively nuclear. Together, these results point to a potential link between the Toll signaling pathway and melanotic tumor induction. Although dl has been shown previously to bind to kappa B-related motifs within the promoter of the antibacterial peptide coding gene diptericin, we find that injury-induced expression of diptericin can occur in the absence of dl. Furthermore, the melanotic tumor phenotype of Toll and cactus is not dl dependent. These data underline the complexity of the Drosophila immune response. Finally, we observed that like other rel proteins, dl can control the level of its own transcription.
Collapse
Affiliation(s)
- B Lemaitre
- Institut de Biologie Moléculaire et Cellulaire, UPR 9022 du CNRS, Strasbourg, France
| | | | | | | | | | | | | |
Collapse
|
32
|
Whalen AM, Steward R. Dissociation of the dorsal-cactus complex and phosphorylation of the dorsal protein correlate with the nuclear localization of dorsal. J Cell Biol 1993; 123:523-34. [PMID: 8227123 PMCID: PMC2200115 DOI: 10.1083/jcb.123.3.523] [Citation(s) in RCA: 110] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The formation of dorsal-ventral polarity in Drosophila requires the asymmetric nuclear localization of the dorsal protein along the D/V axis. This process is regulated by the action of the dorsal group genes and cactus. We show that dorsal and cactus are both phosphoproteins that form a stable cytoplasmic complex, and that the cactus protein is stabilized by its interaction with dorsal. The dorsal-cactus complex dissociates when dorsal is targeted to the nucleus. While the phosphorylation of cactus remains apparently unchanged during early embryogenesis, the phosphorylation state of dorsal correlates with its release from cactus and with its nuclear localization. This differential phosphorylation event is regulated by the dorsal group pathway.
Collapse
Affiliation(s)
- A M Whalen
- Department of Molecular Biology, Princeton University, New Jersey 08544
| | | |
Collapse
|
33
|
Abstract
Embryonic dorsal-ventral polarity in Drosophila is established through a series of successive steps and requires the functions of both maternal and zygotic genes. The graded distribution of the transcription factor dorsal in blastoderm nuclei represents the transition from the maternal to the zygotic program. This results in the activation of specific zygotic genes that act to create the regional pattern along this axis.
Collapse
Affiliation(s)
- R Steward
- Department of Molecular Biology, Princeton University, New Jersey 08544
| | | |
Collapse
|
34
|
Abstract
The maternal-effect gene dorsal encodes the ventral morphogen that is essential for elaboration of ventral and ventrolateral fates in the Drosophila embryo. Dorsal belongs to the rel family of transcription factors and controls asymmetric expression of zygotic genes along the dorsoventral axis. The dorsal protein is cytoplasmic in early embryos, possibly because of a direct interaction with cactus. In response to a ventral signal, dorsal protein becomes partitioned into nuclei of cleavage-stage syncytial blastoderms such that the ventral nuclei have the maximum amount of dorsal protein, and the lateral and dorsal nuclei have progressively less protein. Here we show that transgenic flies containing the dorsal cDNA, which is driven by the constitutively active hsp83 promoter, exhibits rescue of the dorsal- phenotype. Transformed lines were used to increase the level of dorsal protein. Females with dorsal levels roughly twice that of wild-type produced normal embryos, while a higher level of dorsal protein resulted in phenotypes similar to those observed for loss-of-function cactus mutations. By manipulating the cactus gene dose, we found that in contrast to a dorsal/cactus ratio of 2.5 which resulted in fully penetrant weak ventralization, a cactus/dorsal ratio of 3.0 was acceptable by the system. By manipulating dorsal levels in different cactus and dorsal group mutant backgrounds, we found that the relative amounts of ventral signal to that of the dorsal-cactus complex is important for the elaboration of the normal dorsoventral pattern. We propose that in a wild-type embryo, the activities of dorsal and cactus are not independently regulated; excess cactus activity is deployed only if a higher level of dorsal protein is available. Based on these results we discuss how the ventral signal interacts with the dorsal-cactus complex, thus forming a gradient of nuclear dorsal protein.
Collapse
Affiliation(s)
- S Govind
- Department of Molecular Biology, Princeton University, NJ 08544
| | | | | |
Collapse
|
35
|
Abstract
The Drosophila morphogen dorsal, KBF1, NF-kappa B, and the proto-oncogene c-rel belong to the rel family of transcription factors whose function is regulated post-translationally by selective nuclear import. In the early Drosophila embryo, dorsal protein is proposed to be retained in the cytoplasm through its interaction with cactus protein. The maternal dorsal group genes constitute a signal transduction pathway, which results in targeting cytoplasmic dorsal protein into the nuclei of the syncytial blastoderm embryo, in a ventral-to-dorsal gradient. The asymmetric transcriptional regulation of zygotic genes along the dorsoventral axis by the dorsal morphogen gradient establishes embryonic dorsoventral polarity. In the lymphocytes, the functional equivalent of cactus is I kappa B, which appears to retain NF-kappa B in the cytoplasm. This retention is relieved by extracellular signals in tissue culture. NF-kappa B and rel proteins each are known to function as oligomeric complexes. Here we present genetic and biochemical evidence for the existence and functional importance of an oligomeric dorsal complex in vivo.
Collapse
Affiliation(s)
- S Govind
- Department of Molecular Biology, Princeton University, NJ 08544
| | | | | |
Collapse
|
36
|
Abstract
In the Drosophila female the product of the germline stem cell, the cystoblast, gives rise to 16 interconnected cystocytes. One of them differentiates into the oocyte, while the 15 others become polyploid nurse cells. Bic-D is required for the differentiation of an oocyte and hence for fertility. Recessive mutations in Bic-D block the oocyte-specific accumulation of its own and other RNAs. Based on its properties and distribution, the Bic-D protein appears to be a component of a cytoskeletal transport or anchoring system. Additional results suggest that the phosphorylation of the Bic-D protein is essential for its accumulation in the pro-oocyte and that this process leads to the gradual localization to the pro-oocyte of factors required for oocyte differentiation.
Collapse
Affiliation(s)
- B Suter
- Department of Molecular Biology, Princeton University, New Jersey 08544
| | | |
Collapse
|
37
|
Abstract
The maternal determinants of dorsoventral polarity of the Drosophila embryo are derived from somatic and germ-line components of the egg chamber. During oogenesis, asymmetry seems to be established by a signal transduction process. This process is thought to provide the developing embryo with a ventral signal responsible for determining the embryonic axis. Through a set of interactions that may involve signal transduction and proteolytic cascade events, positional information is generated in the form of a graded distribution of dorsal protein in blastoderm nuclei. Different levels of dorsal protein result in asymmetric expression of zygotic genes that ultimately specify cell fate.
Collapse
Affiliation(s)
- S Govind
- Department of Molecular Biology, Princeton University, NJ 08544
| | | |
Collapse
|
38
|
Abstract
dorsal is one of the maternally active dorsal-ventral polarity genes of Drosophila and is homologous to the vertebrate proto-oncogene c-rel. In wild-type embryos, the dorsal protein is found in the cytoplasm during cleavage. After the nuclei migrate to the periphery of the embryo, a ventral-to-dorsal gradient of nuclear dorsal protein is established. The formation of the nuclear gradient is disrupted in mutant embryos from other maternally active dorsal-ventral polarity genes: in dorsalized embryos only cytoplasmic protein is observed, while in ventralized embryos the nuclear gradient is shifted dorsally. My findings suggest that nuclear localization is critical for dorsal to function as a morphogen and that the distribution of the dorsal protein determines cell fate along the dorsal-ventral axis.
Collapse
Affiliation(s)
- R Steward
- Biology Department, Princeton University, New Jersey 08544
| |
Collapse
|
39
|
Suter B, Romberg LM, Steward R. Bicaudal-D, a Drosophila gene involved in developmental asymmetry: localized transcript accumulation in ovaries and sequence similarity to myosin heavy chain tail domains. Genes Dev 1989; 3:1957-68. [PMID: 2576013 DOI: 10.1101/gad.3.12a.1957] [Citation(s) in RCA: 158] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
The Bicaudal-D (Bic-D) gene is essential for the differentiation of the oocyte in Drosophila. Dominant gain-of-function mutations result in the formation of double abdomen embryos. The Bic-D gene was cloned and identified using restriction fragment length polymorphisms, Northern analysis, and transformation rescue. Bic-D RNA accumulates in the oocyte during the earliest stages of oogenesis and is localized anteriorly in later stages. The predicted protein contains several extended amphipathic helices, and its similarity to myosin heavy chain tails, paramyosin, and kinesin suggests a similar type of coiled-coil protein interaction.
Collapse
Affiliation(s)
- B Suter
- Department of Biology, Princeton University, New Jersey 08544-1003
| | | | | |
Collapse
|
40
|
Abstract
dorsal is one of the maternally active dorsal-ventral polarity genes of Drosophila and is closely related to the vertebrate proto-oncogene c-rel. Genetic experiments suggest that dorsal represents one of the last (if not the last) steps in the maternal pathway involved in establishing dorsal-ventral polarity in the early embryo. Even though the dorsal RNA is uniformly distributed in the embryo, we have found that the dorsal protein is specifically localized in peripheral nuclei of syncytial and cellular blastoderm stage embryos, and it is distributed in a ventral-to-dorsal gradient. These findings suggest possible mechanisms for how the dorsal protein may communicate maternal positional information to the zygotic genome.
Collapse
Affiliation(s)
- R Steward
- Department of Biology, Princeton University, New Jersey 08544
| | | | | | | |
Collapse
|
41
|
Pensler JM, Steward R, Lewis SR, Herndon DN. Reconstruction of the burned palm: full-thickness versus split-thickness skin grafts--long-term follow-up. Plast Reconstr Surg 1988; 81:46-9. [PMID: 3275944] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The long-term results of full-thickness (N = 11) and split-thickness (N = 14) skin grafts for reconstitution of the palmar surface following release of palmar burn scar contractures in pediatric patients are compared. Patients treated with full-thickness skin grafts required 1.2 +/- 0.4 operations (mean +/- SD). Patients treated with split-thickness skin grafts required 1.3 +/- 0.6 operations (mean +/- SD). No significant difference in the number of operative procedures was noted. No functional difference existed between the two groups. The use of split-thickness skin grafts provided comparable function without increased operative procedures and was less deforming. Increased use of split-thickness skin grafts following release of palmar burn scar contractures in pediatric patients should be considered.
Collapse
Affiliation(s)
- J M Pensler
- Division of Plastic and Reconstructive Surgery, Shriners Burns Institute, Galveston, Texas
| | | | | | | |
Collapse
|
42
|
Abstract
The Drosophila gene, dorsal, is a maternal effect locus that is essential for the establishment of dorsal-ventral polarity in the developing embryo. The dorsal protein was predicted from the complementary DNA sequence; it is almost 50 percent identical, over an extensive region, to the protein encoded by the avian oncogene v-rel, its cellular homolog, c-rel, and a human c-rel fragment. The oncogene v-rel is highly oncogenic in avian lymphoid, spleen, and bone marrow cells.
Collapse
Affiliation(s)
- R Steward
- Department of Biology, Princeton University, NJ 08544
| |
Collapse
|
43
|
Abstract
The chromosomal region 36C on 2L contains two maternal-effect loci, dorsal (dl) and Bicaudal-D (Bic-D), which are involved in establishing polarity of the Drosophila embryo along the dorsal-ventral and anterior-posterior axes, respectively. To analyze the region genetically, we isolated X-ray-induced dorsal alleles, which we recognized by virtue of the haplo-insufficient temperature-sensitive dorsal-dominant phenotype in progeny of single females heterozygous for a mutagenized chromosome. From the 20,000 chromosomes tested, we isolated three deficiencies, two inversions with breakpoint in dl and one apparent dl point mutant. One of the deficiencies, Df(2L)H20 (36A6,7; 36F1,2) was used to screen for EMS-induced lethal- and maternal-effect mutants mapping in the vicinity of dl and Bic-D. We isolated 44 lethal mutations defining 11 complementation groups. We also recovered as maternal-effect mutations four dl alleles, as well as six alleles of quail and one allele of kelch, two previously identified maternal-effect genes. Through complementation tests with various viable mutants and deficiencies in the region, a total of 18 loci were identified in an interval of about 30 cytologically visible bands. The region was subdivided into seven subregions by deficiency breakpoints. One lethal complementation group as well as the two maternal loci, Bic-D and quail, are located in the same deficiency interval as is dl.
Collapse
|
44
|
|
45
|
Abstract
The establishment of embryonic polarity is a crucial step in pattern formation and morphogenesis. In the fruitfly Drosophila melanogaster, embryonic polarity depends primarily on genes expressed in the female during oogenesis. Mutations in these 'maternal effect' genes can lead to major disruptions in normal pattern formation. Two classes of maternal genes essential for the establishment of polarity in the embryo have been identified. Lesions in one class, the 'bicaudal' genes, disrupt the anterior-posterior axis; lesions in the other class disrupt dorsal-ventral polarity, and in the most extreme cases embryos fail to form any ventral or lateral structures. Genetic studies suggest that the anterior-posterior and dorsal-ventral axes may be independent as the defects observed in mutants from each class seem to be restricted to one axis only. The dorsal (dl) locus is one of the maternal effect genes involved in the establishment of dorsal-ventral polarity. Homozygous dl females produce embryos exhibiting the mutant phenotype--complete lack of dorsal-ventral polarity in the strongest alleles--irrespective of the genotype of the father. Although dl is a maternal effect locus and must be expressed during oogenesis, the gene product, or a substance depending on the normal function of the dl gene, seems to be active early in embryogenesis, as the dl phenotype can be partially rescued by injection of cytoplasm from wild-type cleavage-stage embryos. Here we report the molecular cloning of the dorsal locus and a study of its expression.
Collapse
|
46
|
Wright TR, Beermann W, Marsh JL, Bishop CP, Steward R, Black BC, Tomsett AD, Wright EY. The genetics of dopa decarboxylase in Drosophila melanogaster. IV. The genetics and cytology of the 37B10-37D1 region. Chromosoma 1981; 83:45-58. [PMID: 6790250 DOI: 10.1007/bf00286015] [Citation(s) in RCA: 36] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Of 204 mutations located in the 8-12 band Df(2L)130 region, 37B9-C1,2;37D1-2, 199 have been assigned to twelve lethal genes and one visible gene (hook). The 13 genes are not evenly distributed. Twelve, (possibly all thirteen) are in the seven band region 37B10-C4 giving a gene-to-band ratio of almost two. Only one gene, 1(2)37Cf, may be in the four band region 37C5-7, and none are localized in band 37D1. In situ hybridization places the dopa decarboxylase structural gene, Ddc, in or very close to band 37C1,2 (Hirsh and Davidson, 1981). The chi methyl dopa hypersensitive gene, 1(2) and, is 0.002 map units distal to Ddc. Df(2L)VA17, 37C1,2; 37F5-38A1 may actually break in the 37C1,2 singlet. It places six genes, hook, 1(2) and, and four lethal genes, in a maximum of five bands, 37B10, 11, 12, 13 and perhaps part of the 37C1,2 singlet and localizes six genes, Ddc plus five lethal genes, in a maximum of three bands; probably part of the 37C1,2 singlet plus bands, C3, and C4. Wild type activity of five of twelve lethal genes is necessary for female fertility. --Band 37C5 puffs at the time of pupariation; Puff Stages 8-10. Twelve of eighteen alleles of 1(2)37Cf have been examined as heterozygotes over CyO and none affect the appearance of a homozygous 37C5 puff. --Of the 204 mutations considered here only one Ddcpl, affects the function of more than one gene. It eliminates Ddc+ and 1(2)37Ca+ function and at 30 degrees C reduces 1(2)37Ce+ function. It is not a deficiency but could be a polar mutant.
Collapse
|
47
|
Steward R, Gehring WJ. A hybrid plasmid containing Drosophila melanogaster DNA sequences complementary to the large mitochondrial ribosomal RNA. Gene 1981; 14:131-5. [PMID: 6790350 DOI: 10.1016/0378-1119(81)90155-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
|
48
|
|
49
|
Abstract
A single intratesticular injection of TEPA or Thio-TEPA induced a period of infertility lasting 1-2 months. Restoration of fertility was characterized by a reduction of the litter size resulting from the first inpregnation post-treatment. There was no evidence of tissue pathogenesis 6-12 months after treatment.
Collapse
|
50
|
Dudler R, Egg AH, Kubli E, Artavanis-Tsakonas S, Gehring WJ, Steward R, Schedl P. Transfer RNA genes of Drosophila melanogaster. Nucleic Acids Res 1980; 8:2921-37. [PMID: 6776487 PMCID: PMC324135 DOI: 10.1093/nar/8.13.2921] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Three recombinant plasmids containing randomly sheared genomic D. melanogaster tRNAs have been identified and characterized in detail. One of these, the plasmid 14C4, has a D. melanogaster (Dm) DNA segment of 18 kb, and has three tRNA2Arg and two tRNAAsN genes. The second plasmid, 38B10, has tRNAHis genes, while the third plasmid, 63H5, contains coding sequences for tRNA2Asp. The Dm DNA segments in each recombinant plasmid are derived from unique cytogenetic loci. 14C4 is from 84 F, 38B10 is from 48 F and 63H5 is from 70 A.
Collapse
|