MOLECULAR-CLONING OF MOUSE DOC2-ALPHA AND DISTRIBUTION OF ITS MESSENGER-RNA IN ADULT-MOUSE BRAIN

We have previously isolated from a human brain cDNA library, a new pro tein having two C2-like domains which interact with Ca2+ and phospholi pid, and named Doc2 alpha. Doc2 alpha is abundantly expressed in brain , where it is highly concentrated on the synaptic vesicle fraction, an d is implicated in Ca2+-dependent exocytosis. We have isolated here a mouse Doc2 alpha cDNA and determined the localization of its mRNA in a dult mouse brain. The amino acid sequence of the mouse Doc2 alpha cDNA is 92% identical with that of the human counterpart. Northern blot an alysis and in situ hybridization on adult mouse brain sections have re vealed that Doc2 alpha is predominantly expressed in mouse brain, wher e it is expressed in neuronal cells, but not in non-neuronal cells. Do c2 alpha is highly expressed in the olfactory bulb, cerebral cortex, h ippocampus, amygdaloid complex, and ventromedial hypothalamus nucleus, but not in the cerebellum, caudate-putamen, or ventral thalamus. Thes e results indicate that Doc2 alpha is expressed heterogeneously in mou se brain, where it is predominantly expressed in neuronal cells, and s uggest that Doc2 alpha plays a specific role in the area where it is e xpressed.