Abstract
The genes related to response of various stresses seem to be particularly prone to alternative splicing in higher plants. We demonstrated previously that the transcription of Arabidopsis SR protein, atSR45a, is induced by high-light irradiation. Here we studied the function of atSR45a protein involved in spliceosome assembly. Six types of mRNA variant (atSR45a-1a - e, -2) were generated from the atSR45a pre-mRNA by the alternative splicing event. The expression of atSR45a-1a and atSR45a-2 mRNAs was increased by high-light irradiation. Next, we analyzed the interaction of atSR45a-1a and atSR45a-2 proteins with other splicing factors by a yeast two-hybrid assay. The atSR45a-1a and atSR45a-2 proteins interacted with U1-70K, a key protein involved in the 5'-splice site recognition. In addition, they also interacted with themselves or each other. These results suggest that atSR45a serves as a component in constitutive and/or alternative splicing.
