MOLECULAR-CLONING AND CHARACTERIZATION OF A GENE THAT ENCODES A MYC-RELATED PROTEIN IN ARABIDOPSIS

In plants, MYC-related proteins function as transcription factors invo lved in anthocyanin production and trichome development. We cloned a g ene, Atmycl, and its corresponding cDNA, that encodes for a MYC-relate d protein from Arabidopsis thaliana. The putative protein has a basic/ helix-loop-helix motif at the C-terminus and a highly homologous regio n with that of the maize B/R family at the N-terminus. The promoter re gion of Atmyc1 contains a Sph box (CATGCATG) that is known as a cis-re gulatory element conferring seed-specific expression. In fact, Atmyc1 transcripts were more abundant in developing seeds than in stems and l eaves where trichomes are normally expressed. Restriction fragment len gth polymorphism mapping demonstrated that Atmycl is located on the up per region of chromosome 4, which clearly indicates that Atmyc1 is dis tinct from the ttg (transparent testa glabrous) locus that affects bot h trichome development and anthocyanin biosynthesis.