PMI40, an intron-containing gene required for early steps in yeast mannosylation.
Mol Cell Biol
; 12(7): 2924-30, 1992 Jul.
Article
en En
| MEDLINE
| ID: mdl-1377774
We have previously described a temperature-sensitive pmi40-1 mutant of Saccharomyces cerevisiae which is defective in glycosylation and secretion because of a thermolabile phosphomannose isomerase (PMI) activity. Inactivation of PMI at the restrictive temperature of 37 degrees C prevents synthesis of the GDP-mannose and dolichol-phosphate-mannose required for a number of critical mannosyl transfer reactions and results in cell death. Here, we report the isolation of the PMI40 gene by complementation of the corresponding mutation. The PMI40 gene contains an efficiently spliced intron which differs from the majority of those so far identified in S. cerevisiae in that it is short and the branch-forming structure has an AACTAAC motif replacing the highly conserved consensus TACTAAC. The 48.2-kDa protein predicted to be encoded by PMI40 contains amino acid sequences corresponding to those of internal peptides derived from purified S. cerevisiae PMI. Deletion of the PMI40 coding sequence results in a strain requiring D-mannose for growth. The PMI40 gene is located on chromosome V, and its transcription is increased 12-fold when cells are grown on D-mannose as sole carbon source instead of D-glucose. PMI enzyme activity, however, is not increased in D-mannose-grown cells, and PMI protein levels remain constant, suggesting that the PMI40 gene is subject to additional levels of regulation.
Texto completo:
1
Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Saccharomyces cerevisiae
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Regulación Fúngica de la Expresión Génica
/
Manosa
/
Manosa-6-Fosfato Isomerasa
Idioma:
En
Revista:
Mol Cell Biol
Año:
1992
Tipo del documento:
Article
País de afiliación:
Suiza
Pais de publicación:
Estados Unidos