Prof Dr. Norbert F. Käufer
Prof. em. Dr. Herbert Gutz †13.11.2016
Our model organism Schizosaccharomyces pombe (fission yeast) has three chromosomes with a size of 5.6, 4.5 and 2.5 Mbp, respectively. The cells divide by binary fission with a doubling time of 2-4 hours. Starvation induces two haploid cells of opposite mating type to fuse and to form a zygote. The zygotes then undergo meiosis and develop into an ascus containing four spores, which are released from the ascus and grow out as haploid cell clones when nutrients are added.
The life cycle of S. pombe
The advantage of using fission yeast as an experimental system is twofold: First, the existence of powerful procedures of classical and molecular genetics as well as cytological and biochemical techniques and the availability of the complete genomic sequence (www.pombase.org). Second, the finding that many basic cellular mechanisms such as cell cycle regulation, gene expression, pre-mRNA splicing and DNA repair are closely related to mechanisms found in mammalian systems.
In our group we are interested in the process and regulation of pre-mRNA splicing in fission yeast. In eukaryotic cells pre-mRNA consists of coding (exons) and non-coding (introns) regions. The introns are removed during the splicing process, the exons are joined together and the mature mRNA is formed. The splicing reaction is catalyzed by the spliceosome, a large ribonucleoprotein complex, which recognizes the beginning and the end of an intron via their exon1/5' -splice site, branch sequence and 3' -splice site. There are still several open questions how this mechanism works in detail and some of these questions are addressed by our group.