Dma1-dependent degradation of Septation Initiation Network proteins during meiosis inSchizosaccharomyces pombe

Abstract

The Schizosaccharomyces pombe septation initiation network (SIN) is required for cytokinesis during vegetative growth and for spore formation during meiosis. Regulation of the SIN during mitosis has been studied extensively, but less is known about its meiotic regulation. Here, we show that several aspects of SIN regulation differ between mitosis and meiosis. First, the presence of GTPbound Spg1p is not the main determinant of the timing of Cdc7p and Sid1p association with the spindle pole body (SPB) during meiosis. Second, the localisation dependencies of SIN proteins differ from those in mitotic cells, suggesting a modified functional organisation of the SIN during meiosis. Third, there is stage-specific degradation of SIN components in meiosis; Byr4p is degraded after meiosis I, whereas the degradation of Cdc7p, Cdc11p and Sid4p occurs after the second meiotic division and depends upon the ubiquitin ligase Dma1p. Finally, Dma1p-dependent degradation is not restricted to the SIN, as we show that Dma1p is needed for the degradation of Mcp6p (also known as Hrs1p) during meiosis I. Taken together, these data suggest that stage-specific targeted proteolysis plays an important role in regulating meiotic progression.

Analysis ofS. pombeSIN protein SPB-association reveals two genetically separable states of the SIN

“…Data from biological repeats for a given cell type were also found to have no statistical differences, so data from multiple experiments have been pooled to generate the graphs presented for each marker or mutant. The majority of GFP-tagged strains used in this study have been described previously (see Krapp and Simanis, 2014 and references therein). Strains expressing slp1…”

Pombe's thirteen – control of fission yeast cell division by the septation initiation network

“…The SIN might be regulated differently during meiosis and mitosis (Krapp and Simanis, 2014). For example, generation of Spg1p-GTP is not sufficient to recruit Cdc7p to the SPB.…”

Analysis of the S. pombe Meiotic Proteome Reveals a Switch from Anabolic to Catabolic Processes and Extensive Post-transcriptional Regulation

“…Stage-specific protein degradation also plays an important role; for example, the meiosis-specific anaphase promoting complex (APC/C) inhibitor Mes1p prevents complete degradation of Cdc13p at the end of meiosis I (Izawa et al, 2005;Kimata et al, 2008), degradation of Sgo1p permits sister chromatid separation (Kitajima et al, 2004(Kitajima et al, , 2006Rabitsch et al, 2004;Riedel et al, 2006) and degradation of Hrs1p/Mcp6p allows formation of the meiosis I spindle (Funaya et al, 2012;Tanaka et al, 2005). Some SIN proteins are also degraded during meiosis (Krapp and Simanis, 2014).…”