Meiosis-dependent mRNA splicing of the fission yeastSchizosaccharomyces pombe mes1+gene

✍ Scribed by Masao Kishida; Tsutomu Nagai; Yukinobu Nakaseko; Chikashi Shimoda

• Publisher: Springer-Verlag
• Year: 1994
• Tongue: English
• Weight: 963 KB
• Volume: 25
• Category: Article
• ISSN: 0172-8083
• DOI: 10.1007/bf00351668

✦ Synopsis

The mesl + gene of the fission yeast Schizosaccharomyces pombe is essential for the second meiotic division. We have cloned a 1.1-kb HindIII fragment containing mesl § by complementation from an S. pombe genomic library. Sequencing of the genomic and cDNA fragments indicates the existence of one small intron of 75 nucleotides, although both the 5' (G/GTTAGT) and 3" (CAG/T) intron-exon junctions deviate from the consensus sequences proposed for S. pombe. The putative translation product of the mature mesl + mRNA is a 11-kDa protein of 101 amino acids which has no significant homology to any previously-reported proteins. Disruption of mesl has no effect on cell growth but causes an arrest of meiosis before the second meiotic division. Northern-blot analysis revealed that mesl + was preferentially transcribed under conditions of nitrogen starvation. When a h 9~ homothallic strain was shifted to a nitrogen-deficient medium, a pre-mRNA accumulated and then was gradually processed to generate a mature mRNA. This splicing did not occur in either a heterothallic haploid strain or in a homothallic mei2 mutant strain which was defective in the initiation of meiosis. Expression of the first exon alone was not able to suppress the mesl null allele. These results indicate that mesl § is required for the completion of meiosis, that splicing is required for the function of the rues1 § gene, and that this splicing requires the function of the mei2 § product.