STA1, a stress-upregulated nuclear protein, is required for pre-mRNA splicing, mRNA turnover and stress tolerance

In plants, many gene transcripts are very unstable, which is important for the tight control of their temporal and spatial expression patterns. To identify cellular factors controlling the stability of unstable mRNAs in plants, we used luciferase imaging in Arabidopsis to isolate a recessive mutant, stabilized 1 (sta1), with enhanced stability of the normally unstable luciferase transcript. The sta1 mutation also causes the stabilization of some endogenous gene transcripts and has a range of developmental and stress response phenotypes. STA1 encodes a nuclear protein similar to the human U5 snRNP-associated 102-kDa protein and to the yeast pre-mRNA splicing factor Prp1p and Prp6p. STA1 expression is up-regulated by cold stress, and the sta1 mutant is defective in the splicing of the cold-induced COR15A gene. Our results show that STA1 is a pre-mRNA splicing factor required for not only splicing but also the turnover of unstable transcripts and that it has an important role in plant responses to abiotic stresses.

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Lee BH, Kapoor A, Zhu J, Zhu JK