โ Scribed by Torrance G. Cooper
No coin nor oath required. For personal study only.
Louvain-la-Neuve was the site of the Tenth International Conference on Yeast Genetics and Molecular Biology. During 24 plenary presentations, 18 evening workshops and over 200 posters, members of the international community participated in an exhaustive exchange of information about Saccharomyces cerevisiae and a few related organisms. From the depth and breadth of information presented, one could conservatively conclude that S. cerevisiae has become a favorite model for studying the structure and operation of eucaryotic cells. To review, even briefly, all of the topics discussed would be impossible. Therefore, a limited number of topics has been chosen. They provide a flavor of the information exchanged and an assessment of new and potentially important findings.
The meeting was opened by presentation of an engaging hypothesis derived from studies of mitochondrial genetics and DNA sequencing. The gene encoding cytochrome b is composed of a mosaic of six exons and five introns. It was suggested that one of the introns encodes a protein which participates in the removal of intron sequences from the cytochrome b gene transcript, i.e. an RNA splicing enzyme or maturase. This model was consistent with data presented by several investigators and supported by four important observations. Strains harboring missense mutations within the intron sequence (box 3) were unable to process the transcripts derived from the cytochrome b gene. Nonsense, but not missense mutations in the exon adjacent to the 5' end of the box 3 region generated a similar phenotype prompting a suggestion that the N-terminus of the presumptive maturase was located in that exon. Box 3 intron mutations could be suppressed by drugs such as paromomycin which cause translational misreading; exon mutations were not suppressible under these conditons. DNA sequencing of the box 3 region revealed a long open reading frame. Colinearity could also be established between
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