C Palleschi — Page 2 | PubMed Health

PubMedDate not supplied

Symmetrical transcription in the tRNA region of the mitochondrial genome of Saccharomyces cerevisiae.

The occurrence of discrete transcripts originating from the non-coding strand of the yeast mitochondrial genome is described. The region under investigation is localized in the large tRNA gene cluster between the LSU ribosomal RNA and OXI 1 genes. The transcripts originating from the non-coding strand were detected in a wild-type strain and in a rho- mutant. Their size range includes transcripts of about 2000 nucleotides able to accommodate more than one "anti-tRNA". In some cases their extremities can be mapped near highly-conserved nonanucleotides that could function as origins of transcription. The involvement of the tRNA-processing machinery in the cleavage of these transcripts is also hypothesized.

Base Sequence↗

PubMedDate not supplied

Mutants of Kluyveromyces lactis with altered protein glycosylation are affected in cell wall morphogenesis.

We isolated spontaneous mutants resistant to sodium orthovanadate in the biotechnologically significant yeast Kluyveromyces lactis. Resistance behaved as a recessive character in all mutants analyzed. Four genes were defined by complementation analysis, from vga1 to vga4. These mutants showed defects in N-linked as well as O-linked glycosylation processes. In addition, the mutants exhibited sensitivity to the aminoglycoside hygromycin B and to calcofluor white, with the exception of vga4; this mutant grew in the presence of the antibiotic as well as the parental wild type and was resistant to calcofluor. The mutations were accompanied by alterations in the cell wall structure, as revealed by the delocalization of chitin, changes in cell shape and size and by the clumpy aspect of the cultures. The mutants isolated provide basic tools for molecular and cellular analysis of glycosylation processes in K. lactis.

Cell Wall↗