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Lasser M, Sun N, Xu Y, Wang S, Drake S, Law K, Gonzalez S, Wang B, Drury V, Castillo O, Zaltsman Y, Dea J, Bader E, McCluskey KE, State MW, Willsey AJ, Willsey HR. Pleiotropy of autism-associated chromatin regulators. Development 2023; 150:dev201515. [PMID: 37366052 PMCID: PMC10399978 DOI: 10.1242/dev.201515] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Accepted: 06/19/2023] [Indexed: 06/28/2023]
Abstract
Gene ontology analyses of high-confidence autism spectrum disorder (ASD) risk genes highlight chromatin regulation and synaptic function as major contributors to pathobiology. Our recent functional work in vivo has additionally implicated tubulin biology and cellular proliferation. As many chromatin regulators, including the ASD risk genes ADNP and CHD3, are known to directly regulate both tubulins and histones, we studied the five chromatin regulators most strongly associated with ASD (ADNP, CHD8, CHD2, POGZ and KMT5B) specifically with respect to tubulin biology. We observe that all five localize to microtubules of the mitotic spindle in vitro in human cells and in vivo in Xenopus. Investigation of CHD2 provides evidence that mutations present in individuals with ASD cause a range of microtubule-related phenotypes, including disrupted localization of the protein at mitotic spindles, cell cycle stalling, DNA damage and cell death. Lastly, we observe that ASD genetic risk is significantly enriched among tubulin-associated proteins, suggesting broader relevance. Together, these results provide additional evidence that the role of tubulin biology and cellular proliferation in ASD warrants further investigation and highlight the pitfalls of relying solely on annotated gene functions in the search for pathological mechanisms.
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Affiliation(s)
- Micaela Lasser
- Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, San Francisco, CA 94143, USA
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Nawei Sun
- Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, San Francisco, CA 94143, USA
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Yuxiao Xu
- Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, San Francisco, CA 94143, USA
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Sheng Wang
- Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, San Francisco, CA 94143, USA
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Sam Drake
- Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, San Francisco, CA 94143, USA
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Karen Law
- Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, San Francisco, CA 94143, USA
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Silvano Gonzalez
- Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, San Francisco, CA 94143, USA
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Belinda Wang
- Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, San Francisco, CA 94143, USA
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, USA
- Langley Porter Psychiatric Institute, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Vanessa Drury
- Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, San Francisco, CA 94143, USA
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Octavio Castillo
- Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, San Francisco, CA 94143, USA
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Yefim Zaltsman
- Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, San Francisco, CA 94143, USA
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Jeanselle Dea
- Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, San Francisco, CA 94143, USA
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Ethel Bader
- Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, San Francisco, CA 94143, USA
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Kate E. McCluskey
- Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, San Francisco, CA 94143, USA
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Matthew W. State
- Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, San Francisco, CA 94143, USA
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, USA
- Langley Porter Psychiatric Institute, University of California, San Francisco, San Francisco, CA 94143, USA
- Quantitative Biosciences Institute, University of California, San Francisco, San Francisco, CA 94143, USA
| | - A. Jeremy Willsey
- Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, San Francisco, CA 94143, USA
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, USA
- Quantitative Biosciences Institute, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Helen Rankin Willsey
- Department of Psychiatry and Behavioral Sciences, University of California, San Francisco, San Francisco, CA 94143, USA
- Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA 94143, USA
- Chan Zuckerberg Biohub - San Francisco, San Francisco, CA 94158, USA
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Lasser M, Bolduc J, Murphy L, O'Brien C, Lee S, Girirajan S, Lowery LA. 16p12.1 Deletion Orthologs are Expressed in Motile Neural Crest Cells and are Important for Regulating Craniofacial Development in Xenopus laevis. Front Genet 2022; 13:833083. [PMID: 35401697 PMCID: PMC8987115 DOI: 10.3389/fgene.2022.833083] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Accepted: 03/09/2022] [Indexed: 12/03/2022] Open
Abstract
Copy number variants (CNVs) associated with neurodevelopmental disorders are characterized by extensive phenotypic heterogeneity. In particular, one CNV was identified in a subset of children clinically diagnosed with intellectual disabilities (ID) that results in a hemizygous deletion of multiple genes at chromosome 16p12.1. In addition to ID, individuals with this deletion display a variety of symptoms including microcephaly, seizures, cardiac defects, and growth retardation. Moreover, patients also manifest severe craniofacial abnormalities, such as micrognathia, cartilage malformation of the ears and nose, and facial asymmetries; however, the function of the genes within the 16p12.1 region have not been studied in the context of vertebrate craniofacial development. The craniofacial tissues affected in patients with this deletion all derive from the same embryonic precursor, the cranial neural crest, leading to the hypothesis that one or more of the 16p12.1 genes may be involved in regulating neural crest cell (NCC)-related processes. To examine this, we characterized the developmental role of the 16p12.1-affected gene orthologs, polr3e, mosmo, uqcrc2, and cdr2, during craniofacial morphogenesis in the vertebrate model system, Xenopus laevis. While the currently-known cellular functions of these genes are diverse, we find that they share similar expression patterns along the neural tube, pharyngeal arches, and later craniofacial structures. As these genes show co-expression in the pharyngeal arches where NCCs reside, we sought to elucidate the effect of individual gene depletion on craniofacial development and NCC migration. We find that reduction of several 16p12.1 genes significantly disrupts craniofacial and cartilage formation, pharyngeal arch migration, as well as NCC specification and motility. Thus, we have determined that some of these genes play an essential role during vertebrate craniofacial patterning by regulating specific processes during NCC development, which may be an underlying mechanism contributing to the craniofacial defects associated with the 16p12.1 deletion.
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Affiliation(s)
- Micaela Lasser
- Department of Biology, Boston College, Chestnut Hill, MA, United States
| | - Jessica Bolduc
- Department of Biology, Boston College, Chestnut Hill, MA, United States
| | - Luke Murphy
- Department of Biology, Boston College, Chestnut Hill, MA, United States
| | - Caroline O'Brien
- Department of Biology, Boston College, Chestnut Hill, MA, United States
| | - Sangmook Lee
- Department of Biology, Boston College, Chestnut Hill, MA, United States
| | - Santhosh Girirajan
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, State College, PA, United States
| | - Laura Anne Lowery
- Alfred B. Nobel Section of Hematology and Medical Oncology, Boston University School of Medicine and Boston Medical Center, Boston, MA, United States
- *Correspondence: Laura Anne Lowery,
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Pizzo L, Lasser M, Yusuff T, Jensen M, Ingraham P, Huber E, Singh MD, Monahan C, Iyer J, Desai I, Karthikeyan S, Gould DJ, Yennawar S, Weiner AT, Pounraja VK, Krishnan A, Rolls MM, Lowery LA, Girirajan S. Functional assessment of the "two-hit" model for neurodevelopmental defects in Drosophila and X. laevis. PLoS Genet 2021; 17:e1009112. [PMID: 33819264 PMCID: PMC8049494 DOI: 10.1371/journal.pgen.1009112] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2020] [Revised: 04/15/2021] [Accepted: 03/16/2021] [Indexed: 12/13/2022] Open
Abstract
We previously identified a deletion on chromosome 16p12.1 that is mostly inherited and associated with multiple neurodevelopmental outcomes, where severely affected probands carried an excess of rare pathogenic variants compared to mildly affected carrier parents. We hypothesized that the 16p12.1 deletion sensitizes the genome for disease, while "second-hits" in the genetic background modulate the phenotypic trajectory. To test this model, we examined how neurodevelopmental defects conferred by knockdown of individual 16p12.1 homologs are modulated by simultaneous knockdown of homologs of "second-hit" genes in Drosophila melanogaster and Xenopus laevis. We observed that knockdown of 16p12.1 homologs affect multiple phenotypic domains, leading to delayed developmental timing, seizure susceptibility, brain alterations, abnormal dendrite and axonal morphology, and cellular proliferation defects. Compared to genes within the 16p11.2 deletion, which has higher de novo occurrence, 16p12.1 homologs were less likely to interact with each other in Drosophila models or a human brain-specific interaction network, suggesting that interactions with "second-hit" genes may confer higher impact towards neurodevelopmental phenotypes. Assessment of 212 pairwise interactions in Drosophila between 16p12.1 homologs and 76 homologs of patient-specific "second-hit" genes (such as ARID1B and CACNA1A), genes within neurodevelopmental pathways (such as PTEN and UBE3A), and transcriptomic targets (such as DSCAM and TRRAP) identified genetic interactions in 63% of the tested pairs. In 11 out of 15 families, patient-specific "second-hits" enhanced or suppressed the phenotypic effects of one or many 16p12.1 homologs in 32/96 pairwise combinations tested. In fact, homologs of SETD5 synergistically interacted with homologs of MOSMO in both Drosophila and X. laevis, leading to modified cellular and brain phenotypes, as well as axon outgrowth defects that were not observed with knockdown of either individual homolog. Our results suggest that several 16p12.1 genes sensitize the genome towards neurodevelopmental defects, and complex interactions with "second-hit" genes determine the ultimate phenotypic manifestation.
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Affiliation(s)
- Lucilla Pizzo
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, United States of America
| | - Micaela Lasser
- Department of Biology, Boston College, Chestnut Hill, MA, United States of America
| | - Tanzeen Yusuff
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, United States of America
| | - Matthew Jensen
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, United States of America
| | - Phoebe Ingraham
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, United States of America
| | - Emily Huber
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, United States of America
| | - Mayanglambam Dhruba Singh
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, United States of America
| | - Connor Monahan
- Department of Biology, Boston College, Chestnut Hill, MA, United States of America
| | - Janani Iyer
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, United States of America
| | - Inshya Desai
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, United States of America
| | - Siddharth Karthikeyan
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, United States of America
| | - Dagny J. Gould
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, United States of America
| | - Sneha Yennawar
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, United States of America
| | - Alexis T. Weiner
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, United States of America
| | - Vijay Kumar Pounraja
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, United States of America
| | - Arjun Krishnan
- Department of Computational Mathematics, Science and Engineering, Michigan State University, East Lansing, MI, United States of America
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, United States of America
| | - Melissa M. Rolls
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, United States of America
| | - Laura Anne Lowery
- Department of Medicine, Boston University Medical Center, Boston, MA, United States of America
| | - Santhosh Girirajan
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, United States of America
- Department of Anthropology, The Pennsylvania State University, University Park, PA, United States of America
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Singh MD, Jensen M, Lasser M, Huber E, Yusuff T, Pizzo L, Lifschutz B, Desai I, Kubina A, Yennawar S, Kim S, Iyer J, Rincon-Limas DE, Lowery LA, Girirajan S. NCBP2 modulates neurodevelopmental defects of the 3q29 deletion in Drosophila and Xenopus laevis models. PLoS Genet 2020; 16:e1008590. [PMID: 32053595 PMCID: PMC7043793 DOI: 10.1371/journal.pgen.1008590] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 02/26/2020] [Accepted: 12/30/2019] [Indexed: 12/12/2022] Open
Abstract
The 1.6 Mbp deletion on chromosome 3q29 is associated with a range of neurodevelopmental disorders, including schizophrenia, autism, microcephaly, and intellectual disability. Despite its importance towards neurodevelopment, the role of individual genes, genetic interactions, and disrupted biological mechanisms underlying the deletion have not been thoroughly characterized. Here, we used quantitative methods to assay Drosophila melanogaster and Xenopus laevis models with tissue-specific individual and pairwise knockdown of 14 homologs of genes within the 3q29 region. We identified developmental, cellular, and neuronal phenotypes for multiple homologs of 3q29 genes, potentially due to altered apoptosis and cell cycle mechanisms during development. Using the fly eye, we screened for 314 pairwise knockdowns of homologs of 3q29 genes and identified 44 interactions between pairs of homologs and 34 interactions with other neurodevelopmental genes. Interestingly, NCBP2 homologs in Drosophila (Cbp20) and X. laevis (ncbp2) enhanced the phenotypes of homologs of the other 3q29 genes, leading to significant increases in apoptosis that disrupted cellular organization and brain morphology. These cellular and neuronal defects were rescued with overexpression of the apoptosis inhibitors Diap1 and xiap in both models, suggesting that apoptosis is one of several potential biological mechanisms disrupted by the deletion. NCBP2 was also highly connected to other 3q29 genes in a human brain-specific interaction network, providing support for the relevance of our results towards the human deletion. Overall, our study suggests that NCBP2-mediated genetic interactions within the 3q29 region disrupt apoptosis and cell cycle mechanisms during development. Rare copy-number variants, or large deletions and duplications in the genome, are associated with a wide range of neurodevelopmental disorders. The 3q29 deletion confers an increased risk for schizophrenia and autism. To understand the conserved biological mechanisms that are disrupted by this deletion, we systematically tested 14 individual homologs and 314 pairwise interactions of 3q29 genes for neuronal, cellular, and developmental phenotypes in Drosophila melanogaster and Xenopus laevis models. We found that multiple homologs of genes within the deletion region contribute towards developmental defects, such as larval lethality and disrupted cellular organization. Interestingly, we found that NCBP2 acts as a key modifier gene within the region, enhancing the developmental phenotypes of each of the homologs for other 3q29 genes and leading to disruptions in apoptosis and cell cycle pathways. Our results suggest that multiple genes within the 3q29 region interact with each other through shared mechanisms and jointly contribute to neurodevelopmental defects.
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Affiliation(s)
- Mayanglambam Dhruba Singh
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Matthew Jensen
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Micaela Lasser
- Department of Biology, Boston College, Chestnut Hill, Massachusetts, United States of America
| | - Emily Huber
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Tanzeen Yusuff
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Lucilla Pizzo
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Brian Lifschutz
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Inshya Desai
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Alexis Kubina
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Sneha Yennawar
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Sydney Kim
- Department of Biology, Boston College, Chestnut Hill, Massachusetts, United States of America
| | - Janani Iyer
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
| | - Diego E Rincon-Limas
- Department of Neurology, McKnight Brain Institute, University of Florida, Gainesville, Florida, United States of America
| | - Laura Anne Lowery
- Department of Biology, Boston College, Chestnut Hill, Massachusetts, United States of America
- Department of Medicine, Boston University Medical Center, Boston, Massachusetts, United States of America
| | - Santhosh Girirajan
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, Pennsylvania, United States of America
- Department of Anthropology, Pennsylvania State University, University Park, Pennsylvania, United States of America
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Lasser M, Pratt B, Monahan C, Kim SW, Lowery LA. The Many Faces of Xenopus: Xenopus laevis as a Model System to Study Wolf-Hirschhorn Syndrome. Front Physiol 2019; 10:817. [PMID: 31297068 PMCID: PMC6607408 DOI: 10.3389/fphys.2019.00817] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Accepted: 06/11/2019] [Indexed: 01/09/2023] Open
Abstract
Wolf–Hirschhorn syndrome (WHS) is a rare developmental disorder characterized by intellectual disability and various physical malformations including craniofacial, skeletal, and cardiac defects. These phenotypes, as they involve structures that are derived from the cranial neural crest, suggest that WHS may be associated with abnormalities in neural crest cell (NCC) migration. This syndrome is linked with assorted mutations on the short arm of chromosome 4, most notably the microdeletion of a critical genomic region containing several candidate genes. However, the function of these genes during embryonic development, as well as the cellular and molecular mechanisms underlying the disorder, are still unknown. The model organism Xenopus laevis offers a number of advantages for studying WHS. With the Xenopus genome sequenced, genetic manipulation strategies can be readily designed in order to alter the dosage of the WHS candidate genes. Moreover, a variety of assays are available for use in Xenopus to examine how manipulation of WHS genes leads to changes in the development of tissue and organ systems affected in WHS. In this review article, we highlight the benefits of using X. laevis as a model system for studying human genetic disorders of development, with a focus on WHS.
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Affiliation(s)
- Micaela Lasser
- Department of Biology, Boston College, Chestnut Hill, MA, United States
| | - Benjamin Pratt
- Department of Biology, Boston College, Chestnut Hill, MA, United States
| | - Connor Monahan
- Department of Biology, Boston College, Chestnut Hill, MA, United States
| | - Seung Woo Kim
- Department of Biology, Boston College, Chestnut Hill, MA, United States
| | - Laura Anne Lowery
- Department of Biology, Boston College, Chestnut Hill, MA, United States
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Abstract
Neurons depend on the highly dynamic microtubule (MT) cytoskeleton for many different processes during early embryonic development including cell division and migration, intracellular trafficking and signal transduction, as well as proper axon guidance and synapse formation. The coordination and support from MTs is crucial for newly formed neurons to migrate appropriately in order to establish neural connections. Once connections are made, MTs provide structural integrity and support to maintain neural connectivity throughout development. Abnormalities in neural migration and connectivity due to genetic mutations of MT-associated proteins can lead to detrimental developmental defects. Growing evidence suggests that these mutations are associated with many different neurodevelopmental disorders, including intellectual disabilities (ID) and autism spectrum disorders (ASD). In this review article, we highlight the crucial role of the MT cytoskeleton in the context of neurodevelopment and summarize genetic mutations of various MT related proteins that may underlie or contribute to neurodevelopmental disorders.
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Affiliation(s)
- Micaela Lasser
- Department of Biology, Boston College, Chestnut Hill, MA, United States
| | - Jessica Tiber
- Department of Biology, Boston College, Chestnut Hill, MA, United States
| | - Laura Anne Lowery
- Department of Biology, Boston College, Chestnut Hill, MA, United States
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7
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Simionescu M, Ghinea N, Fixman A, Lasser M, Kukes L, Simionescu N, Palade GE. The cerebral microvasculature of the rat: structure and luminal surface properties during early development. J Submicrosc Cytol Pathol 1988; 20:243-61. [PMID: 3395964] [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] [Grants] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The development of the cerebral microvasculature of the rat was studied during three successive postnatal periods, namely: 1) neonatal period, i.e., 1 to 9 days after birth (capillary sprouting period); 2) myelinization period, i.e., 10 to 20 days; and 3) young adult period, i.e., 2 to 3 months. The survey covered structural aspects and distribution of binding sites for anionic or cationic probes and for albumin-gold complexes on the luminal surface of the microvascular endothelium. The salient results are: a) an extensive development of the endoplasmic reticulum of endothelial cells during the first period (presumably in relation with the production of basement membrane components); b) the high surface density of coated pits and coated vesicles that peaks during the myelinization period; c) the paucity of plasmalemmal vesicle and their differential distribution (their volume density is higher in the endothelium of arterioles than in that of capillaries and venules); d) the existence of an extensive smooth surface tubular system in the cytoplasm of endothelial cells, whose structural connections and functional significance remains to be established; and e) the presence of pericytes with elaborate interactions with endothelia in the early developmental periods. Labeling by perfused tracers indicates an uneven patchy distribution of binding sites for cationic ferritin (generally limited to the plasmalemma proper) and a more even distribution of binding sites for cationic and anionic hemeundecapeptides. Binding patterns did not change during the developmental periods studied. No binding sites were detected for albumin-gold complexes.
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Affiliation(s)
- M Simionescu
- Institute of Cellular Biology and Pathology, Bucharest, Romania
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Lasser M, Daniel V. Altered regulation of cyclic AMP-dependent protein kinase in a mouse lymphoma cell line. Biochim Biophys Acta 1977; 482:41-51. [PMID: 193571 DOI: 10.1016/0005-2744(77)90352-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The ability of cyclic AMP to inhibit growth, cause cytolysis and induce synthesis of cyclic AMP-phosphodiesterase in S49.1 mouse lymphoma cells is deficient in cells selected on the basis of their resistance to killing by 2 mM dibutyryl cyclic AMP. The properties of the cyclic AMP-dependent protein kinase (ATP:protein phosphotransferase, EC 2.7.1.37) in the cyclic AMP-sensitive (S) and cyclic AMP-resistant (R) lymphoma cells were comparatively studied. The cyclic AMP-dependent protein kinase activity or R cells cytosol exhibits an apparent Ka for activation by cyclic AMP 100-fold greater than that of the enzyme from the parental S cells. The free regulatory and catalytic subunits from both S and R kinase are thermolabile, when associated in the holoenzyme the two subunits are more stable to heat inactivation in R kinase than in S kinase. The increased heat stability of R kinase is observed however only for the enzyme in which the catalytic and cyclic AMP-binding activities are expressed at high cyclic AMP concentrations (10(-5)--10(-4) M), the activities expressed at low cyclic AMP concentrations (10(-9)--10(-6) M) being thermolabile. The regulatory subunit of S kinase can be stabilized against heat inactivation by cyclic AMP binding both at 2-10(-7) and 10(-5) M cyclic AMP concentrations. In contrast, the regulatory subunit-cyclic AMP complex from R kinase is stable to heat inactivation only when formed in the presence of high cyclic AMP concentrations (10(-5)M). The findings indicate that the transition from a cyclic AMP-sensitive to a cyclic AMP-resistant lymphoma cell phenotype is related to a structural alteration in the regulatory subunit of the cyclic AMP-dependent protein kinase which has affected the protein's affinity for cyclic AMP and its interaction with the catalytic subunit.
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Daniel V, Lasser M, Negreanu J. Proceedings: Cytolysis of cultured lymphoma cells by cyclic AMP. Isr J Med Sci 1975; 11:1199. [PMID: 173679] [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: 12/13/2022]
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Schramm M, Feinstein H, Naim E, Lang E, Lasser M. Epinephrine binding to the catecholamine receptor and activation of the adenylate cyclase in erythrocyte membranes (hormone receptor- -adrenergic receptor-cyclic AMP-turkey). Proc Natl Acad Sci U S A 1972; 69:523-7. [PMID: 4501130 PMCID: PMC426494 DOI: 10.1073/pnas.69.2.523] [Citation(s) in RCA: 52] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Turkey erythrocyte membranes showed specific binding of [(3)H]epinephrine. The concentration of hormone required for half-maximal binding (30 muM) was the same as that required for half-maximal activation of the adenylate cyclase located in the same membrane preparation. The binding reaction at 37 degrees C reached completion during the first minute of incubation, which agrees well with the known rapidity of the biological response to catecholamines. Specific binding was abolished by heating the membranes 1 min at 100 degrees C. Chromatography of the bound (3)H, after its extraction from the membranes, indicated that the hormone had fully retained its chemical structure. Epinephrine binding was inhibited by the beta-adrenergic blocking agent propranolol, which also inhibited the activation of adenylate cyclase by the hormone. The specificity of phenethylamine derivatives in displacing [(3)H]epinephrine from the binding sites showed that a typical catecholamine receptor was responsible for the binding. Displacement of the bound hormone by analogs lacking the catechol group was more extensive at 37 degrees C than at 0 degrees C. Some of the analogs that displaced epinephrine from the binding site caused only a feeble activation of the adenylate cyclase, but were able to inhibit the activation of the enzyme by epinephrine. Thus, binding to a catecholamine receptor on a membrane preparation is an essential, but insufficient, condition to elicit a response.
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Selinger Z, Naim E, Lasser M. ATP-dependent calcium uptake by microsomal preparations from rat parotid and submaxillary glands. Biochim Biophys Acta 1970; 203:326-34. [PMID: 4245535 DOI: 10.1016/0005-2736(70)90147-1] [Citation(s) in RCA: 80] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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