Preliminary Analysis On Function Of CK1A Gene In Arabidopsis

Casein kinase 1 (casein kinase 1, CKIA) which belongs to a family of serine/threonine protein kinases have special physical and chemical properties, that involved in many diverse and important cellular functions. Casein kinase 1 exists in yeast, mammals and other eukaryotes. It is distributed mainly in cytoplasm, nucleus, cell membrane and the cytoskeleton and plays a key role of life. Few people study the specific gene function on this family, and physiological functions of the family in plant almost remain unknown. It will play a significant role to study gene physiological functions of this family.In this study, we aligned the CK family gene protein sequences by using Clustal W software and constructed phylogenetic tree. In the present study, we mainly studied the physiological function on CKIA gene of the CK family. The functional domain prediction about CKIA amino acid sequences was analysed. The 963bp upstream sequence of the start codon of CKIA was gained from the website (www.arabidopsis.org).The CKIA gene regulatory regions were anlysed by plant promoter cis-acting element analysis Web site (plantCARE). The results showed that the regulatory regions had a large number of light-related regulatory elements, such as ATCT-motif, G-box, Box 4, Box 1, also a lot of the stress-induced-related elements. Therefore CKIA gene transcription may be induced by light signals or environmental stress, and the ultimate expressed protein is likely involved in light signal and stress signal transduction.The CKIA gene was cloned into the downstream of the 35S promoter of plant expression vector of GW-GFP. The plant expression vector of 35S:GFP:CK1A was constructed. Transient expression analysis indicated that GFP-CK1A fusion protein was mainly localized in the nucleus of onion epidermal cells. The yeast two-hybrid analysis demonstrated that CKIA and CRY2 can be interacted in vivo under blue light, which indicates that CKIA may play important roles in blue light signal induction of Arabidopsis.To further study CKIA gene function, its expression characteristics were studied unsing semi-quantitative RT-PCR. The results showed that CKIA was highly expressed in flowers, stems and roots, but less in leaves and leafstalks. Furthermore, the CKIA gene expression can be induced by blue light. Its expression level was significantly increased after 12 h light treatment, and declined after 24 h light treatment. At the same time, the prokaryotic expression of this gene was studied using pColdTF vector and its recombinant protein was successfully detected. These data may provide a valuable reference for further study of the physiological function of CK1A gene.