Differential expression patterns and a novel interaction factor of Damaged DNA Binding Protein 1A (DDB1A) and DDB1B in Arabidopsis thaliana

Damaged DNA Binding protein 1 (DDB1) is a bridging protein of CULLIN4 (CUL4)-RING E3 ligase complex, which is involved in multiple biological processes including DNA repair, parental imprinting, epigenetic regulation and flowering time. In Arabidopsis (Arabidopsis thaliana), there are two paralogous genes of DDB1, i.e. DDB1A and DDB1B. In this study, we fused the promoter sequences of DDB1A (−1 bp to 1697 bp 5’ to ATG) and DDB1B (−1 bp to 1655 bp 5’ to ATG) to the GUS gene, respectively, and we then analyzed differential expression patterns of DDB1A and DDB1B using the transgenic PDDB1A::GUS and PDDB1B::GUS plants. The results showed that DDB1B was specifically expressed in the style, and abscisic acid (ABA) might increase the expression level of DDB1A in the meristematic tissues in the light. Using yeast two-hybrid, we found that both DDB1A and DDB1B interacted with CDT2 (also referred to as DDB1-CUL4 ASSOCIATED FACTOR2, DCAF2). Transcript analysis showed that a transcript retains one intron (85 bp in length), suggesting that CDT2 may be involved in the regulation of alternative splicing (AS). This work might provide a clue for further investigating the roles of DDB1A and DDB1B in multiple physiological processes and lay a solid foundation for in depth studying the functions of CDT2 in Arabidopsis.