Abstract: The nucleotide sequence of a cDNA clone from Arabidopsis thaliana (L.) Heynh. "ecotype Columbia" was determined. The open reading frame encoded a protein, AtJ3, which was highly homologous to DnaJ protein of E. coli. The predicted amino acid sequence of AtJ3 contained J-domain, G or GFdomain, Cysteine-rich Zn finger-like sequence, which were all characteristic of this class of DnaJ homologues. And the C-teminal of At J3 was -CAQQ, a farnesylation motif. Using primers based on the cDNA, the corresponding gene AtJ3 was isolated and sequenced. The structure of this gene consisted of six exons interrupted by five introns. The results of Southern analysis indicated that AtJ3 was a single structure gene. At J3 was censtitutively expressed in cotyledons, leaves, roots, flowers, and siliques based on Northern analysis. Heat shock at 32 ℃ led to increase in mRNA expression in leaves.

Key words: cDNA, Gene, Intron, Molecular chaperone, Gene structure