JDD1, a novel member of the DnaJ family, is expressed in the germinal zoneof the rat brain

We identified a novel gene encoding a new member of the DnaJ family, JDD1 ( J domain of DnaJ-like-protein 1), from the rat. The cloned JDD1 cDNA is 168 9 bp in size and its deduced amino acid sequence consists of 259 amino acid residues. Immunoblot analysis revealed that JDD1 protein is approximately 30 kDa in size. JDD1 has a J domain that is unique to the DnaJ family but l acks the G/F region (a region that is rich in the amino acids glycine and p henylalanine) and the zinc finger region (also known as the cysteine-rich r egion)-both characteristic to the DnaJ, JDD1 mRNA is expressed heterogeneou sly in vivo. In the central nervous system, JDD1 mRNA expression is confine d to the germinal (ventricular and subventricular) zone where, except for c ells situated deepest in the ventricular zone, neurons and glias are genera ted and then differentiate during the embryonic period. Expression of JDD1 mRNA in the subventricular zone persists after birth. In addition to the br ain, its robust expression is notable in the liver, lung, cortex of the kid ney, and several other tissues in the embryo. (C) 2001 Academic Press.