ISSN:
1617-4623
Keywords:
Kluyveromyces lactis
;
Transcriptional regulation
;
Promoter
;
Sugar transport
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary TheRAG1 gene encodes a membrane protein involved in the low-affinity glucose/fructose transport system of the yeastKluyveromyces lactis. Analysis of steady-state mRNA levels analysis and quantitation of expression by β-galactosidase fromRAG1-lacZ fusions assays revealed that theRAG1 gene was poorly expressed in cells grown under gluconeogenesis conditions, but was induced more than ten-fold when they were grown on various sugars. These sugars included glucose, fructose, mannose, sucrose, raffinose, as well as galactose. Nucleotide sequence and deletion analysis of the 5′ fianking region of theRAG1 gene showed that an essentialcis-acting element required for induced transcription of theRAG1 gene resided between − 615 and − 750 from the coding sequence. This region contained a 22 by purine stretch, and a pair of 11 by direct repeat sequences. The 11 by repeats harbor a CCAAT motif, a consensus sequence for binding of the yeast and mammalian HAP2/3/4-type protein complex. The transcription of theRAG1 gene was dramatically affected by three unlinked mutations,rag4, rag5 andrag8. We discuss the possible roles ofRAG4,RAG5 andRAG8 gene products in the expression of theRAG1 gene, as well as the importance of the inducibleRAG1 gene in the fermentative growth ofK. lactis.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00587566
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