Pds1p Is Required for Meiotic Recombination and Prophase I Progression inSaccharomyces cerevisiae

Abstract

Sister-chromatid separation at the metaphase-anaphase transition is regulated by a proteolytic cascade. Destruction of the securin Pds1p liberates the Esp1p separase, which ultimately targets the mitotic cohesin Mcd1p/Scc1p for destruction. Pds1p stabilization by the spindle or DNA damage checkpoints prevents sister-chromatid separation while mutants lacking PDS1 (pds1D) are temperature sensitive for growth due to elevated chromosome loss. This report examined the role of the budding yeast Pds1p in meiotic progression using genetic, cytological, and biochemical assays. Similar to its mitotic function, Pds1p destruction is required for metaphase I-anaphase I transition. However, even at the permissive temperature for growth, pds1D mutants arrest with prophase I spindle and nuclear characteristics. This arrest was partially suppressed by preventing recombination initiation or by inactivating a subset of recombination checkpoint components. Further studies revealed that Pds1p is required for recombination in both double-strand-break formation and synaptonemal complex assembly. Although deleting PDS1 did not affect the degradation of the meiotic cohesin Rec8p, Mcd1p was precociously destroyed as cells entered the meiotic program. This role is meiosis specific as Mcd1p destruction is not altered in vegetative pds1D cultures. These results define a previously undescribed role for Pds1p in cohesin maintenance, recombination, and meiotic progression. M EIOSIS generates haploid gametes through a specialized cell division process that consists of one round of DNA replication followed by two nuclear divisions. The first meiotic division is unique to meiosis for two reasons. First, during the extended prophase I, homologous chromosomes synapse and undergo high levels of genetic recombination that is essential for the correct chromosome alignment at metaphase I (Kupiec et al. 1997). Second, following resolution of the recombination intermediates, the spindle makes monopolar attachments to the sister chromatids permitting the execution of meiosis I or the reductional division. Meiosis II resembles mitosis in that the replicated sister chromatids segregate to opposite poles.Meiotic recombination establishes chromosome alignment essential for accurate segregation during the first meiotic division. It follows therefore that the first step in this process, i.e., the formation of doublestrand breaks (DSBs), is also a critical event (Keeney et al. 1997). To date, in budding yeast, at least 10 proteins are required for this process (reviewed in Baudat and Keeney 2001;Arora et al. 2004;Borde 2007). Some of these proteins are meiosis specific whereas others also have roles in mitotically dividing cells. Significantly, apart from Spo11p, which initiates DSB formation (Keeney et al. 1997), little is known about the biochemical function of the individual components of this complex and how they are regulated.The proper execution of recombination and other meiotic landmark events is governed by several checkpoint pathways (reviewe...

Mutually dependent degradation of Ama1p and Cdc20p terminates APC/C ubiquitin ligase activity at the completion of meiotic development in yeast

“…The strains used in this study (Table 1) are isogenic to RSY335 [61] and are derived from an SK1 background [62]. The only exception to this is RSY1337 that is isogenic a W303a-related strain RSY10 [63].…”

The signal between the initiation of recombination and the first division of meiosis in Saccharomyces cervisiae

“…This arrest can be partially suppressed by a spo11 mutation. Cooper et al (2009) also suggest that Pds1 has a role in promoting break formation. This is underscored by the absence of DSB formation and heteroallelic recombination in pds1 ts mutants that haave been sporulated at the non-permissive temperature (Cooper et al, 2009).…”

“…When correct attachment is achieved, the APC ubiquitinates securin and targets it for destruction by the 26S proteosome. This allows separase (Esp1)to become active and the kleisin subunit of cohesins to be cleaved (Cooper et al, 2009;Nasmyth and Haering, 2005).…”

“…APC/C is only activated when each chromosome is correctly attached to spindle fibers radiating from opposite poles (amphitelic attachment) as opposed to the same pole (syntelic attachment). When attachment is achieved, the APC ubiquitinates the inhibitory chaperone protein securin (encoded by PDS1 in S. cerevisiae) targeting it for destruction by the 26S proteosome (Cooper et al, 2009;Nasmyth and Haering, 2005) (Fig. 3-1B).…”

“…During mitosis Pds1 must be fully degraded to allow sister chromosomes to segregate equationally. A temperature-sensitive (ts) mutant of PDS1 shifted to the nonpermissive temperature at the start of sporulation causes an arrest in prophase I suggesting that Pds1 is essential for meiotic division (Cooper et al, 2009). This arrest can be partially suppressed by a spo11 mutation.…”