Paralogous ribosomal protein l32-1 and l32-2 in fission yeast may function distinctively in cellular proliferation and quiescence by changing the ratio of rpl32 paralogs.
Fission yeast cells express Rpl32-2 highly while Rpl32-1 lowly in log phase; in contrast, expression of Rpl32-1 raises and reaches a peak level while Rpl32-2 is downregulated to a low basic level when cells enter into stationary phase. Overexpression of Rpl32-1 inhibits cell growth while overexpression of Rpl32-2 does not. Deleting rpl32-2 impairs cell growth more severely than deleting rpl32-1 does. Cell growth impaired by deleting either paralog can be rescued completely by reintroducing rpl32-2, but only partly by rpl32-1. Overexpression of Rpl32-1 inhibits cell division, yielding 4c DNA and multiple septa, while overexpressed Rpl32-2 promotes it. Transcriptomics analysis proved that Rpl32 paralogs regulate expression of a subset of genes related with cell division and stress response in a distinctive way. This functional difference of the two paralogs is due to their difference of 95(th) amino acid residue. The significance of a competitive inhibition between Rpl32 paralogs on their expression is discussed.
Sun L, Yang X, Chen F, Li R, Li X, Liu Z, Gu Y, Gong X, Liu Z, Wei H, Huang Y, Yuan S