RNP1, A NEW RIBONUCLEOPROTEIN GENE OF THE YEAST SACCHAROMYCES-CEREVISIAE

A previously unidentified ribonucleoprotein (RNP) gene of yeast has be en cloned and sequenced. The gene, named RNP1, was found adjacent to a previously sequenced gene encoding the second gene for ribosomal prot ein L4. RNP1 contains two RNA Recognition Motifs (RRM), [alternatively known as RNA binding Domains (RBD)], but unlike most RNP genes does n ot contain any auxillary simple sequence domains. The first RRM (RRM1) most resembles RRM domains found in the hnRNP A/B class of RNP protei ns. The second RRM (RRM2) most resembles a RRM so far seen only in the single RRM of the yeast SSB1 gene. Two null mutants of RNP1 that were created, a frameshift disruption and a complete deletion of the gene, were viable, demonstrating that the gene is not essential for cell gr owth. Two double null mutants of yeast RNP genes that were created (DE LTARNP1/DELTASSB1 and DELTASSB1/DELTANPL3) were also viable. A fragmen t identical in size to the RRM1 domain could be amplified by PCR from the DNA of fungi, plants, and animals, using primers matching the ends of this domain, indicating that the structure of RRM1 is conserved. A nother potential open reading frame on the same cloned fragment of DNA encodes a gene product whose structure resembles that of a seven-tran smembrane-segment membrane receptor protein.