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Zaqout S, Mannaa A, Klein O, Krajewski A, Klose J, Luise-Becker L, Elsabagh A, Ferih K, Kraemer N, Ravindran E, Makridis K, Kaindl AM. Proteome changes in autosomal recessive primary microcephaly. Ann Hum Genet 2023; 87:50-62. [PMID: 36448252 DOI: 10.1111/ahg.12489] [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] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 11/16/2022] [Accepted: 11/18/2022] [Indexed: 12/05/2022]
Abstract
BACKGROUND/AIM Autosomal recessive primary microcephaly (MCPH) is a rare and genetically heterogeneous group of disorders characterized by intellectual disability and microcephaly at birth, classically without further organ involvement. MCPH3 is caused by biallelic variants in the cyclin-dependent kinase 5 regulatory subunit-associated protein 2 gene CDK5RAP2. In the corresponding Cdk5rap2 mutant or Hertwig's anemia mouse model, congenital microcephaly as well as defects in the hematopoietic system, germ cells and eyes have been reported. The reduction in brain volume, particularly affecting gray matter, has been attributed mainly to disturbances in the proliferation and survival of early neuronal progenitors. In addition, defects in dendritic development and synaptogenesis exist that affect the excitation-inhibition balance. Here, we studied proteomic changes in cerebral cortices of Cdk5rap2 mutant mice. MATERIAL AND METHODS We used large-gel two-dimensional gel (2-DE) electrophoresis to separate cortical proteins. 2-DE gels were visualized by a trained observer on a light box. Spot changes were considered with respect to presence/absence, quantitative variation and altered mobility. RESULT We identified a reduction in more than 30 proteins that play a role in processes such as cell cytoskeleton dynamics, cell cycle progression, ciliary functions and apoptosis. These proteome changes in the MCPH3 model can be associated with various functional and morphological alterations of the developing brain. CONCLUSION Our results shed light on potential protein candidates for the disease-associated phenotype reported in MCPH3.
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Affiliation(s)
- Sami Zaqout
- Department of Basic Medical Sciences, College of Medicine, QU Health, Qatar University, Doha, Qatar
| | - Atef Mannaa
- Higher Institute of Engineering and Technology, New Borg AlArab City, Alexandria, Egypt.,Inserm U1192, Laboratoire Protéomique, Réponse Inflammatoire & Spectrométrie de Masse (PRISM), Université de Lille, Lille, France
| | - Oliver Klein
- BIH Center for Regenerative Therapies BCRT, Charité-Universitätsmedizin Berlin, Berlin, Germany.,Berlin Institute of Health, Charité-Universitätsmedizin Berlin (BIH), Berlin, Germany
| | - Angelika Krajewski
- BIH Center for Regenerative Therapies BCRT, Charité-Universitätsmedizin Berlin, Berlin, Germany.,Berlin Institute of Health, Charité-Universitätsmedizin Berlin (BIH), Berlin, Germany
| | - Joachim Klose
- Charité-Universitätsmedizin, Institute of Human Genetics, Berlin, Germany
| | - Lena Luise-Becker
- Charité-Universitätsmedizin Berlin, Institute of Cell Biology and Neurobiology, Berlin, Germany.,Charité-Universitätsmedizin Berlin, Center for Chronically Sick Children (Sozialpädiatrisches Zentrum, SPZ), Berlin, Germany.,Department of Pediatric Neurology, Charité-Universitätsmedizin, Berlin, Germany
| | - Ahmed Elsabagh
- Department of Basic Medical Sciences, College of Medicine, QU Health, Qatar University, Doha, Qatar
| | - Khaled Ferih
- Department of Basic Medical Sciences, College of Medicine, QU Health, Qatar University, Doha, Qatar
| | - Nadine Kraemer
- Charité-Universitätsmedizin Berlin, Institute of Cell Biology and Neurobiology, Berlin, Germany.,Charité-Universitätsmedizin Berlin, Center for Chronically Sick Children (Sozialpädiatrisches Zentrum, SPZ), Berlin, Germany.,Department of Pediatric Neurology, Charité-Universitätsmedizin, Berlin, Germany
| | - Ethiraj Ravindran
- Charité-Universitätsmedizin Berlin, Institute of Cell Biology and Neurobiology, Berlin, Germany.,Charité-Universitätsmedizin Berlin, Center for Chronically Sick Children (Sozialpädiatrisches Zentrum, SPZ), Berlin, Germany.,Department of Pediatric Neurology, Charité-Universitätsmedizin, Berlin, Germany
| | - Konstantin Makridis
- Charité-Universitätsmedizin Berlin, Institute of Cell Biology and Neurobiology, Berlin, Germany.,Charité-Universitätsmedizin Berlin, Center for Chronically Sick Children (Sozialpädiatrisches Zentrum, SPZ), Berlin, Germany.,Department of Pediatric Neurology, Charité-Universitätsmedizin, Berlin, Germany
| | - Angela M Kaindl
- Charité-Universitätsmedizin Berlin, Institute of Cell Biology and Neurobiology, Berlin, Germany.,Charité-Universitätsmedizin Berlin, Center for Chronically Sick Children (Sozialpädiatrisches Zentrum, SPZ), Berlin, Germany.,Department of Pediatric Neurology, Charité-Universitätsmedizin, Berlin, Germany
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Rale MJ, Romer B, Mahon BP, Travis SM, Petry S. The conserved centrosomin motif, γTuNA, forms a dimer that directly activates microtubule nucleation by the γ-tubulin ring complex (γTuRC). eLife 2022; 11:e80053. [PMID: 36515268 PMCID: PMC9859039 DOI: 10.7554/elife.80053] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Accepted: 12/07/2022] [Indexed: 12/15/2022] Open
Abstract
To establish the microtubule cytoskeleton, the cell must tightly regulate when and where microtubules are nucleated. This regulation involves controlling the initial nucleation template, the γ-tubulin ring complex (γTuRC). Although γTuRC is present throughout the cytoplasm, its activity is restricted to specific sites including the centrosome and Golgi. The well-conserved γ-tubulin nucleation activator (γTuNA) domain has been reported to increase the number of microtubules (MTs) generated by γTuRCs. However, previously we and others observed that γTuNA had a minimal effect on the activity of antibody-purified Xenopus γTuRCs in vitro (Thawani et al., eLife, 2020; Liu et al., 2020). Here, we instead report, based on improved versions of γTuRC, γTuNA, and our TIRF assay, the first real-time observation that γTuNA directly increases γTuRC activity in vitro, which is thus a bona fide γTuRC activator. We further validate this effect in Xenopus egg extract. Via mutation analysis, we find that γTuNA is an obligate dimer. Moreover, efficient dimerization as well as γTuNA's L70, F75, and L77 residues are required for binding to and activation of γTuRC. Finally, we find that γTuNA's activating effect opposes inhibitory regulation by stathmin. In sum, our improved assays prove that direct γTuNA binding strongly activates γTuRCs, explaining previously observed effects of γTuNA expression in cells and illuminating how γTuRC-mediated microtubule nucleation is regulated.
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Affiliation(s)
- Michael J Rale
- Department of Molecular Biology, Princeton UniversityPrincetonUnited States
| | - Brianna Romer
- Department of Molecular Biology, Princeton UniversityPrincetonUnited States
| | - Brian P Mahon
- Department of Molecular Biology, Princeton UniversityPrincetonUnited States
| | - Sophie M Travis
- Department of Molecular Biology, Princeton UniversityPrincetonUnited States
| | - Sabine Petry
- Department of Molecular Biology, Princeton UniversityPrincetonUnited States
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Wang X, Rosales JL, Gao X, Lee KY. Centromeric chromatin integrity is compromised by loss of Cdk5rap2, a transcriptional activator of CENP-A. Biomed Pharmacother 2021; 138:111463. [PMID: 33725591 DOI: 10.1016/j.biopha.2021.111463] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 02/22/2021] [Accepted: 03/03/2021] [Indexed: 11/21/2022] Open
Abstract
Centromeres are chromosomal loci where kinetochores assemble to ensure faithful chromosome segregation during mitosis. CENP-A defines the loci by serving as an epigenetic marker that recruits other centromere components for a functional structure. However, the mechanism that controls CENP-A regulation of centromeric chromatin integrity remains to be explored. Separate studies have shown that loss of CENP-A or the Cdk5 regulatory subunit associated protein 2 (Cdk5rap2), a key player in mitotic progression, triggers the occurrence of lagging chromosomes. This prompted us to investigate a potential link between CENP-A and Cdk5rap2 in the maintenance of centromeric chromatin integrity. Here, we demonstrate that loss of Cdk5rap2 causes reduced CENP-A expression while exogenous Cdk5rap2 expression in cells depleted of endogenous Cdk5rap2 restores CENP-A expression. Indeed, we show that Cdk5rap2 is a nuclear protein that acts as a positive transcriptional regulator of CENP-A. Cdk5rap2 interacts with the CENP-A promoter and upregulates CENP-A transcription. Accordingly, loss of Cdk5rap2 causes reduced level of centromeric CENP-A. Exogenous CENP-A expression partially inhibits the occurrence of lagging chromosomes in Cdk5rap2 knockdown cells, indicating that lagging chromosomes induced by loss of Cdk5rap2 is due, in part, to loss of CENP-A. Aside from manifesting lagging chromosomes, cells depleted of Cdk5rap2, and thus CENP-A, show increased micronuclei and chromatin bridge formation. Altogether, our findings indicate that Cdk5rap2 serves to maintain centromeric chromatin integrity partly through CENP-A.
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Zaqout S, Blaesius K, Wu YJ, Ott S, Kraemer N, Becker LL, Rosário M, Rosenmund C, Strauss U, Kaindl AM. Altered inhibition and excitation in neocortical circuits in congenital microcephaly. Neurobiol Dis 2019; 129:130-143. [PMID: 31102767 DOI: 10.1016/j.nbd.2019.05.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Revised: 04/15/2019] [Accepted: 05/11/2019] [Indexed: 02/06/2023] Open
Abstract
Congenital microcephaly is highly associated with intellectual disability. Features of autosomal recessive primary microcephaly subtype 3 (MCPH3) also include hyperactivity and seizures. The disease is caused by biallelic mutations in the Cyclin-dependent kinase 5 regulatory subunit-associated protein 2 gene CDK5RAP2. In the mouse, Cdk5rap2 mutations similar to the human condition result in reduced brain size and a strikingly thin neocortex already at early stages of neurogenesis that persists through adulthood. The microcephaly phenotype in MCPH arises from a neural stem cell proliferation defect. Here, we report a novel role for Cdk5rap2 in the regulation of dendritic development and synaptogenesis of neocortical layer 2/3 pyramidal neurons. Cdk5rap2-deficient murine neurons show poorly branched dendritic arbors and an increased density of immature thin spines and glutamatergic synapses in vivo. Moreover, the excitatory drive is enhanced in ex vivo brain slice preparations of Cdk5rap2 mutant mice. Concurrently, we show that pyramidal neurons receive fewer inhibitory inputs. Together, these findings point towards a shift in the excitation - inhibition balance towards excitation in Cdk5rap2 mutant mice. Thus, MCPH3 is associated not only with a neural progenitor proliferation defect but also with altered function of postmitotic neurons and hence with altered connectivity.
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Affiliation(s)
- Sami Zaqout
- Charité - Universitätsmedizin Berlin, Institute of Cell- and Neurobiology, Charitéplatz 1, 10117 Berlin, Germany; Charité - Universitätsmedizin Berlin, Center for Chronically Sick Children (Sozialpädiatrisches Zentrum, SPZ), Augustenburger Platz 1, 13353 Berlin, Germany; Charité - Universitätsmedizin Berlin, Department of Pediatric Neurology, Augustenburger Platz 1, 13353 Berlin, Germany; Berlin Institute of Health (BIH), Anna-Louisa-Karsch Strasse 2, 10178 Berlin, Germany
| | - Kathrin Blaesius
- Charité - Universitätsmedizin Berlin, Institute of Cell- and Neurobiology, Charitéplatz 1, 10117 Berlin, Germany; Charité - Universitätsmedizin Berlin, Center for Chronically Sick Children (Sozialpädiatrisches Zentrum, SPZ), Augustenburger Platz 1, 13353 Berlin, Germany; Charité - Universitätsmedizin Berlin, Department of Pediatric Neurology, Augustenburger Platz 1, 13353 Berlin, Germany; Berlin Institute of Health (BIH), Anna-Louisa-Karsch Strasse 2, 10178 Berlin, Germany
| | - Yuan-Ju Wu
- Charité - Universitätsmedizin Berlin, NeuroCure, Charitéplatz 1, 10117 Berlin, Germany
| | - Stefanie Ott
- Charité - Universitätsmedizin Berlin, Institute of Cell- and Neurobiology, Charitéplatz 1, 10117 Berlin, Germany
| | - Nadine Kraemer
- Charité - Universitätsmedizin Berlin, Institute of Cell- and Neurobiology, Charitéplatz 1, 10117 Berlin, Germany; Charité - Universitätsmedizin Berlin, Center for Chronically Sick Children (Sozialpädiatrisches Zentrum, SPZ), Augustenburger Platz 1, 13353 Berlin, Germany; Charité - Universitätsmedizin Berlin, Department of Pediatric Neurology, Augustenburger Platz 1, 13353 Berlin, Germany
| | - Lena-Luise Becker
- Charité - Universitätsmedizin Berlin, Institute of Cell- and Neurobiology, Charitéplatz 1, 10117 Berlin, Germany; Charité - Universitätsmedizin Berlin, Center for Chronically Sick Children (Sozialpädiatrisches Zentrum, SPZ), Augustenburger Platz 1, 13353 Berlin, Germany; Charité - Universitätsmedizin Berlin, Department of Pediatric Neurology, Augustenburger Platz 1, 13353 Berlin, Germany
| | - Marta Rosário
- Charité - Universitätsmedizin Berlin, Institute of Cell- and Neurobiology, Charitéplatz 1, 10117 Berlin, Germany
| | - Christian Rosenmund
- Berlin Institute of Health (BIH), Anna-Louisa-Karsch Strasse 2, 10178 Berlin, Germany; Charité - Universitätsmedizin Berlin, NeuroCure, Charitéplatz 1, 10117 Berlin, Germany; Charité - Universitätsmedizin Berlin, Institute of Neurophysiology, Charitéplatz 1, 10117 Berlin, Germany
| | - Ulf Strauss
- Charité - Universitätsmedizin Berlin, Institute of Cell- and Neurobiology, Charitéplatz 1, 10117 Berlin, Germany
| | - Angela M Kaindl
- Charité - Universitätsmedizin Berlin, Institute of Cell- and Neurobiology, Charitéplatz 1, 10117 Berlin, Germany; Charité - Universitätsmedizin Berlin, Center for Chronically Sick Children (Sozialpädiatrisches Zentrum, SPZ), Augustenburger Platz 1, 13353 Berlin, Germany; Charité - Universitätsmedizin Berlin, Department of Pediatric Neurology, Augustenburger Platz 1, 13353 Berlin, Germany; Berlin Institute of Health (BIH), Anna-Louisa-Karsch Strasse 2, 10178 Berlin, Germany.
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Sidhoo S, Rosales JL, Lee KY. Integration of a bacterial gene sequence into a chronic eosinophilic leukemia patient's genome as part of a fusion gene linker. Biomark Res 2017; 5:20. [PMID: 28593047 PMCID: PMC5460404 DOI: 10.1186/s40364-017-0101-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [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: 05/03/2017] [Accepted: 06/01/2017] [Indexed: 11/26/2022] Open
Abstract
Analysis of databases from the human genome project (HGP), the 1000 Genomes Project (1KGP), and The Cancer Genome Atlas (TCGA) revealed bacterial DNA integration into the human somatic genome, particularly in tumor tissues. Fusion genes have also been associated with tumorigenesis and 34 PDGFR fusion genes are linked to hematological malignancies. Here, we determined that a 17-bp homologous sequence in Marinobacter sp. Hb8, Rhodococcus fascians D188, Rhodococcus sp. PBTS2, Micrococcus luteus strain trpE16 and M. luteus NCTC 2665 integrates into the genome of a chronic eosinophilic leukemia patient as part of the linker for the novel CDK5RAP2-PDGFRα fusion gene. The resulting fusion protein that has CDK5RAP2’s self-activating domain and PDGFRa’s tyrosine kinase domain but lacks PDGFRa’s membrane-binding and ligand-dependent activation properties may act together with the integrated bacterial sequence to readily phosphorylate downstream targets, amplify proliferation signals and promote leukemic cancer progression.
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Affiliation(s)
- Saveen Sidhoo
- Arnie Charbonneau Cancer Institute, Departments of Cell Biology & Anatomy, University of Calgary, Calgary, AB T2N 4N1 Canada
| | - Jesusa L Rosales
- Biochemistry & Molecular Biology, University of Calgary, Calgary, AB Canada
| | - Ki-Young Lee
- Arnie Charbonneau Cancer Institute, Departments of Cell Biology & Anatomy, University of Calgary, Calgary, AB T2N 4N1 Canada
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