Arabidopsis IQM2 is Involved in Calmodulin and Blue Light Signaling

抄録

iqm2-1 is a Salk T-DNA insertion line of the IQM2 gene whose T-DNA inserts into the first exon of the gene. IQM2 consists of six exons, and its product contains an IQ motif to which calmodulin (CaM) possibly binds in the absence of calcium ion. Using the yeast two-hybrid system, IQM2 was demonstrated to bind with Arabidopsis CaM2. RT-PCR analyses showed that the IQM2 mRNA was not transcribed downstream of the T-DNA insertion site in the mutant. iqm2-1 showed a long-hypocotyl phenotype in both white- and blue-light conditions, and anthocyanin level of iqm2-1 was lower than that of wild type. These aberrant phenotypes were restored by a complementation experiment using the wild-type IQM2 gene. We also found IQM2 to be localized to the nucleus and its transcription was up-regulated by blue light. Taken together, IQM2 is involved in calmodulin and blue light signaling.