Cloning of Schizosaccharomyces pombe genes encoding the U1, U2, U3 and U4 snRNAs

Schizosaccharomyces pombe contains a group of five relatively abundant small nuclear RNAs (snRNAs) which are immunoprecipitated by human autoimmune antibodies of Sm serotype. The S. pombe RNAs hybridise to probes specific for human U1, U2, U4, U5 and U6 and in each case are similar in size to the human species. A further group of snRNAs from S. pombe are precipitated by antibodies against U3 containing ribonucleoprotein; the most abundant of these species hybridises to a probe specific for human U3. We have cloned the genes encoding U1, U2, U3 and U4 from S. pombe, together with that encoding another abundant snRNA, previously designated SPU43. U2 and U4 are encoded by single-copy genes, while two genes encode U3. The latter are not clustered, since a chromosomal Southern transfer shows them to lie on different chromosomes.