RESUMO
A Schizosaccharomyces pombe spindle pole body (SPB) protein interacts in a two-hybrid system with Dlc1, which belongs to the 14-kDa Tctex-1 dynein light chain family. Green fluorescent protein-tagged Dlc1 accumulated at the SPB throughout the life cycle. During meiotic prophase, Dlc1 was present along astral microtubules and microtubule-anchoring sites on the cell cortex, reminiscent of the cytoplasmic dynein heavy chain Dhc1. In a dlc1-null mutant, Dhc1-dependent nuclear movement in meiotic prophase became irregular in its duration and direction. Dhc1 protein was displaced from the cortex anchors and the formation of microtubule bundle(s) that guide nuclear movement was impaired in the mutant. Meiotic recombination in the dlc1 mutant was reduced to levels similar to that in the dhc1 mutant. Dlc1 and Dhc1 also have roles in karyogamy and rDNA relocation during the sexual phase. Strains mutated in both the dlc1 and dhc1 loci displayed more severe defects in recombination, karyogamy, and sporulation than in either single mutant alone, suggesting that Dlc1 is involved in nuclear events that are independent of Dhc1. S. pombe contains a homolog of the 8-kDa dynein light chain, Dlc2. This class of dynein light chain, however, is not essential in either the vegetative or sexual phases.
Assuntos
Núcleo Celular/metabolismo , Proteínas de Drosophila , Meiose/fisiologia , Proteínas dos Microtúbulos/metabolismo , Proteínas Associadas aos Microtúbulos , Proteínas Nucleares , Recombinação Genética/fisiologia , Schizosaccharomyces/fisiologia , Sequência de Aminoácidos , Animais , Sequência de Bases , Proteínas de Transporte , DNA Ribossômico/metabolismo , Dineínas , Ligação Genética , Proteínas de Fluorescência Verde , Humanos , Proteínas Luminescentes/genética , Proteínas Luminescentes/metabolismo , Proteínas dos Microtúbulos/química , Proteínas dos Microtúbulos/genética , Centro Organizador dos Microtúbulos/metabolismo , Microtúbulos/metabolismo , Dados de Sequência Molecular , Família Multigênica , Proteínas Recombinantes de Fusão/metabolismo , Schizosaccharomyces/citologia , Alinhamento de Sequência , Técnicas do Sistema de Duplo-Híbrido , Região do Complexo-t do GenomaRESUMO
The inaugural version of the InGaP database (Integrative Gene and Protein expression database; http://www.kazusa.or.jp/ingap/index.html) is a comprehensive database of gene/protein expression profiles of 127 mKIAA genes/proteins related to hypothetical ones obtained in our ongoing cDNA project. Information about each gene/protein consists of cDNA microarray analysis, subcellular localization of the ectopically expressed gene, and experimental data using anti-mKIAA antibody such as Western blotting and immunohistochemical analyses. KIAA cDNAs and their mouse counterparts, mKIAA cDNAs, were mainly isolated from cDNA libraries derived from brain tissues, thus we expect our database to contribute to the field of neuroscience. In fact, cDNA microarray analysis revealed that nearly half of our gene collection is predominantly expressed in brain tissues. Immunohistochemical analysis of the mouse brain provides functional insight into the specific area and/or cell type of the brain. This database will be a resource for the neuroscience community by seamlessly integrating the genomic and proteomic information about the mouse KIAA genes/proteins.
Assuntos
Bases de Dados Genéticas , Expressão Gênica , Proteínas do Tecido Nervoso/genética , Software , Animais , Western Blotting , Química Encefálica , Cromatografia Líquida de Alta Pressão , Clonagem Molecular , DNA Complementar/genética , Previsões , Perfilação da Expressão Gênica , Biblioteca Gênica , Genômica , Humanos , Espectrometria de Massas , Camundongos , Nanotecnologia , Proteínas do Tecido Nervoso/biossíntese , Análise de Sequência com Séries de Oligonucleotídeos , Proteínas Associadas a Pancreatite , Proteômica , Especificidade da Espécie , Frações Subcelulares/químicaRESUMO
During meiosis, telomeres cluster and promote homologous chromosome pairing. Telomere clustering requires the interaction of telomeres with the nuclear membrane proteins SUN (Sad1/UNC-84) and KASH (Klarsicht/ANC-1/Syne homology). The mechanism by which telomeres gather remains elusive. In this paper, we show that telomere clustering in fission yeast depends on microtubules and the microtubule motors, cytoplasmic dynein, and kinesins. Furthermore, the γ-tubulin complex (γ-TuC) is recruited to SUN- and KASH-localized telomeres to form a novel microtubule-organizing center that we termed the "telocentrosome." Telocentrosome formation depends on the γ-TuC regulator Mto1 and on the KASH protein Kms1, and depletion of either Mto1 or Kms1 caused severe telomere clustering defects. In addition, the dynein light chain (DLC) contributes to telocentrosome formation, and simultaneous depletion of DLC and dynein also caused severe clustering defects. Thus, the telocentrosome is essential for telomere clustering. We propose that telomere-localized SUN and KASH induce telocentrosome formation and that subsequent microtubule motor-dependent aggregation of telocentrosomes via the telocentrosome-nucleated microtubules causes telomere clustering.