Functional redundancy of paralogs of an anaphase promoting complex/cyclosome subunit in Caenorhabditis elegans meiosis.
ABSTRACT The anaphase promoting complex/cyclosome (APC/C) mediates the metaphase-to-anaphase transition by instructing the ubiquitination and turnover of key proteins at this stage of the cell cycle. We have recovered a gain-of-function allele in an APC5 subunit of the anaphase promoting complex/cyclosome. This finding led us to investigate further the role of APC5 in Caenorhabditis elegans, which contains two APC5 paralogs. We have shown that these two paralogs, such-1 and gfi-3, are coexpressed in the germline but have nonoverlapping expression patterns in other tissues. Depletion of such-1 or gfi-3 alone does not have a notable effect on the meiotic divisions; however, codepletion of these two factors results in meiotic arrest. In sum, the two C. elegans APC5 paralogs have a redundant function during the meiotic divisions.
Full-textDOI: · Available from: Benjamin D Ross, Jun 14, 2015
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ABSTRACT: Oocyte maturation in all species is controlled by a protein complex termed the maturation promoting factor (MPF). MPF is comprised of a cyclin-dependent kinase (CDK) and its partner cyclin, and is regulated by dueling regulatory phosphorylation events on the CDK. In Caenorhabditis elegans, the Wee1/Myt1 ortholog WEE-1.3 provides the inhibitory phosphorylations on CDK-1 that keep MPF inactive and halts meiosis. Prior work has shown that depletion of WEE-1.3 in C. elegans results in precocious oocyte maturation in vivo and a highly penetrant infertility phenotype. This study sought to further define the precocious maturation phenotype and to identify novel interactors with WEE-1.3. We found that WEE-1.3 is expressed throughout the germline and in developing embryos in a perinuclear pattern, and demonstrated that oocytes in WEE-1.3-depleted germlines have begun to transcribe embryonic genes and exhibit inappropriate expression of proteins normally restricted to fertilized eggs. In addition, we performed an RNAi suppressor screen of the infertile phenotype to identify novel factors that, when co-depleted with WEE-1.3, restore fertility to these animals. We screened ~1900 essential genes by RNAi feeding and identified 44 (~2% of the tested genes) that are suppressors of the WEE-1.3 depletion phenotype. The suppressors include many previously unidentified players in the meiotic cell cycle, and represent a pool of potential WEE-1.3 interacting proteins that function during C. elegans oocyte maturation and zygotic development.G3-Genes Genomes Genetics 10/2014; 4(12). DOI:10.1534/g3.114.013649 · 2.51 Impact Factor
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ABSTRACT: Spermatogenesis represents a complex succession of cell division and differentiation events resulting in the continuous formation of spermatozoa. Such a complex program requires precise expression of enzymes and structural proteins which is effected not only by regulation of gene transcription and translation, but also by targeted protein degradation. In this chapter, we review current knowledge about the role of the ubiquitin-proteasome system in spermatogenesis, describing both proteolytic and non-proteolytic functions of ubiquitination. Ubiquitination plays essential roles in the establishment of both spermatogonial stem cells and differentiating spermatogonia from gonocytes. It also plays critical roles in several key processes during meiosis such as genetic recombination and sex chromosome silencing. Finally, in spermiogenesis, we summarize current knowledge of the role of the ubiquitin-proteasome system in nucleosome removal and establishment of key structures in the mature spermatid. Many mechanisms remain to be precisely defined, but present knowledge indicates that research in this area has significant potential to translate into benefits that will address problems in both human and animal reproduction.Advances in Experimental Medicine and Biology 01/2014; 759:181-213. DOI:10.1007/978-1-4939-0817-2_9 · 2.01 Impact Factor
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ABSTRACT: Screening for suppressor mutations is a powerful method to isolate genes that function in a common pathway or process. Because suppressor mutations often do not have phenotypes on their own, cloning of suppressor loci can be challenging. A method combining whole genome sequencing and single nucleotide polymorphism mapping (WGS/SNP mapping) was developed to identify mutations with visible phenotypes in Caenorhabditis elegans (Doitsidou et al. 2010). We show here that WGS/SNP mapping is an efficient method to map suppressor mutations, without the need for prior phenotypic characterization. Using RNA-mediated interference to test candidate loci identified by WGS/SNP mapping, we identified 10 extragenic and six intragenic suppressors of mbk-2, a DYRK family kinase required for the transition from oocyte to zygote. Remarkably, seven suppressors are mutations in cell cycle regulators that extend the timing of the oocyte-to-zygote transition.G3-Genes Genomes Genetics 12/2013; 4(2). DOI:10.1534/g3.113.009126 · 2.51 Impact Factor