High impact information on SSO1

• SSO1 and SSO2 encode small proteins with N-terminal hydrophilic domains and C-terminal hydrophobic tails [1].
• A yeast strain that lacks SSO1 and carries the sso2-1 allele ceases growth and accumulates secretory vesicles at the restrictive temperature [2].
• The same mutation was introduced into SSO1, producing the sso1-1 allele, which also has a temperature-sensitive phenotype, although less pronounced than sso2-1 [2].
• Interestingly, among these candidates, we identified two genes, SSO1 and STU2, involved in protein transport and spindle pole body formation, respectively, suggesting puzzling connections with the translation termination process [3].
• The GenBank Accession Nos are AF307983 (K. lactis SSO1) and AF318314 (K. lactis SEB1) [4].

Biological context of SSO1

• Up to four- or six-fold yields of a heterologous secreted protein, Bacillus alpha-amylase, or an endogenous secreted protein, invertase, were obtained respectively when expressing either one of the SSO genes, SSO1 or SSO2, from the ADH1 promoter on a multicopy plasmid [5].
• Western blots failed to reveal a preferential expression of Sso1p in sporulating cells, indicating that effects on gene expression are unlikely to explain why the SSO1 3'UTR is needed for sporulation [6].

Regulatory relationships of SSO1

• This difference is not due to differential expression, since SSO2 expressed from the SSO1 promoter failed to restore sporulation [2].

Other interactions of SSO1

• We previously have cloned two yeast genes encoding syntaxins, SSO1 and SSO2, as suppressors of the temperature-sensitive sec1-1 mutation [7].
• Mapping of sporulation-specific functions in the yeast syntaxin gene SSO1 [6].

References