Abstract
Genes related to response of various types of stress particularly prone to alternative splicing in higher plants. We have demonstrated that the expression of an Arabidopsis SR protein, atSR45a, is induced by high-light irradiation (Plant Cell Physiol. 48: 1036-1049, 2007). Here we studied the function of atSR45a protein involved in spliceosome. Proteins interacted with atSR45a-2, which was presumed to be a functional form among six types of atSR45a products (atSR45a-1a~e, -2) generated by the alternative splicing event, were screened from Arabidopsis cDNA library by a yeast two-hybrid assay. A key protein involved in the 3'-splice site recognition, U2AF35b, was isolated by the screening. The interaction between atSR45a-2 and U2AF35b in planta was thus directly examined by BiFC analysis. The YFP fluorescence was observed in the nucleus of onion cells co-expressing atSR45a-2 and U2AF35b. These results suggest that atSR45a serves as a component in spliceosome assembly via interaction with splicing factors.
