Identification and characterization of CDS2, a mammalian homolog of the Drosophila CDP-diacylglycerol synthase gene

The general strategies of phototransduction in vertebrates and invertebrate s share many similarities, but differ significantly in their underlying mol ecular machinery. The CDS gene encodes the CDP-diacylglycerol ol synthase ( CDS) enzyme and is required for phototransduction in Drosophila. Using a bi oinformatic approach, we have identified two novel transcripts (CDS1 and CD S2) highly homologous to the Drosophila CDS gene. We isolated and sequenced the CDS2 full-length cDNA and mapped the two genes to human chromosomes 20 p13 (CDS2) and 4q21.1 (CDS1). Sequence analysis revealed that both genes ar e highly homologous to the Drosophila protein (64.4 and 58.6% identity at t he protein level between CDS and CDS2 and between CDS and CDS1, respectivel y). The mouse homologs for both genes were isolated and used in RNA in situ hybridization studies on adult and embryonic mouse tissue sections. These studies showed that Cds2 is highly expressed in the differentiating neurobl asts of the neural retina and in the central nervous system during embryoni c development, while it was not detected in adult retina. Cds1, on the othe r hand, shows a high level of expression in the photoreceptor layer of adul t retina, which strongly suggests a role for Cds1 in phototransduction. Kno wledge of the expression pattern of these genes in mammals may shed light o n the evolution of vision mechanisms and help in the evaluation of candidat e genes for human retinopathies. (C) 1999 Academic Press.