Cwc23, an essential J-protein critical for pre-mRNA splicing with a dispensable J-domain
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ABSTRACT: J-proteins are structurally diverse, obligatory co-chaperones of Hsp70s, each with a highly conserved J-domain that plays a critical role in stimulation of Hsp70âs ATPase activity. The essential protein, Cwc23, is one of 13 J-proteins found in the cytosol and/or nucleus of Saccharomyces cerevisiae. We report that a partial loss-of-function CWC23 mutant has severe, global defects in pre-mRNA splicing. This mutation leads to accumulation of the excised, lariat form of the intron, as well as unspliced pre-mRNA, suggesting a role for Cwc23 in spliceosome disassembly. Such a role is further supported by the observation that this mutation results in reduced interaction between Cwc23 and Ntr1 (SPP382), a known component of the disassembly pathway. However, Cwc23 is a very atypical J-protein. Its J-domain, although functional, is dispensable for both cell viability and pre-mRNA splicing. Nevertheless, strong genetic interactions were uncovered between point mutations encoding alterations in Cwc23âs J-domain and either Ntr1 or Prp43, a DExD/H-box helicase essential for spliceosome disassembly. These genetic interactions suggest that Hsp70-based chaperone machinery does play a role in the disassembly process. Cwc23 provides a unique example of a J-protein; its partnership with Hsp70 plays an auxiliary, rather than a central, role in its essential cellular function. Splicing-sensitive microarrays were used to probe the defects seen when the C-terminal or N-terminal regions of Cwc23 were disrupted.
ORGANISM(S): Saccharomyces cerevisiae
SUBMITTER: Maki Inada
PROVIDER: E-GEOD-18485 | biostudies-arrayexpress |
REPOSITORIES: biostudies-arrayexpress
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