SECRETORY RIBONUCLEASE GENES AND PSEUDOGENES IN TRUE RUMINANTS

Mammalian pancreatic ribonucleases (RNase) form a family of extensivel y studied homologous proteins. Phylogenetic analyses, based on the pri mary structures of these enzymes, indicated that the presence of three homologous enzymes (pancreatic, seminal and brain ribonucleases) in t he bovine species is due to gene duplication events, which occurred du ring the evolution of ancestral ruminants. In this paper the sequences are reported of the coding regions of the orthologues of the three bo vine secretory ribonucleases in hog deer and roe deer, two deer specie s belonging to two different subfamilies of the family Cervidae. The s equences of the 3' untranslated regions of the three different secreto ry RNase genes of these two deer species and giraffe are also presente d. Comparison of these and previously determined sequences of ruminant ribonucleases showed that the brain-type enzymes of giraffe and these deer species exhibit variations in their C-terminal extensions. The s eminal-type genes of giraffe, hog deer and roe deer show all the featu res of pseudogenes. Phylogenetic analyses, based on the complete codin g regions and parts of the 3' untranslated regions of the three differ ent secretory ribonuclease genes of ox, sheep, giraffe and the two dee r species, show that pancreatic, seminal-and brain-type RNases form th ree separate groups. (C) 1998 Elsevier Science B.V. All rights reserve d.