THE DROSOPHILA-MELANOGASTER GENOME CONTAINS A MEMBER OF THE RH T-2/S-GLYCOPROTEIN FAMILY OF RIBONUCLEASE-ENCODING GENES/

Members of the Rh/T-2/S-glycoprotein family of ribonuclease(RNase)-enc oding genes have been found predominantly in fungi, plants and bacteri a, where they have been implicated in functions as diverse as the phos phate-starvation response and self-incompatibility. We report the isol ation and sequence of DmRNase-66B, the first member of this family to be found in an insect genome. This gene was identified by the analysis of a cDNA clone derived from cytological region 66B1-2 of the genome of Drosophila melanogaster. In a search of sequence databases for homo logs of this gene, two animal viral proteins, gp53 of the bovine viral diarrhea virus (BVDV) and gp44/48 of the hog cholera virus (HCV), wer e also found to exhibit the characteristic features of this class of R Nases. In all cases, the proteins contain two conserved pentameric ami no-acid regions that have been shown to lie in the active site of thes e RNases. A series of Cys residues are also conserved in all members o f this gene family. The discovery of members of this family of genes i n an insect genome indicates that these RNases are widely conserved an d play important roles in the animal, as well as the plant and prokary otic kingdoms.