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Comparative analysis in three fungi reveals structurally and functionally conserved regions in the Mig1 repressor
J P Cassart1, J Ostling, H Ronne
1Unité de Recherches en Biologie Moléculaire, Facultés Norte-Darne de la Paix, Namur, Belgium.
Molecular & General Genetics : MGG
|June 1, 1997
Summary
The Kluyveromyces marxianus Mig1 (KmMig1) protein functions similarly to its Saccharomyces cerevisiae counterpart, repressing gene expression in response to glucose. Conserved motifs in KmMig1 are crucial for its function and interactions within S. cerevisiae.
Area of Science:
- * Molecular and Cellular Biology
- * Yeast Genetics
- * Gene Regulation
Background:
- * Mig1 repressor is central to glucose repression in *Saccharomyces cerevisiae*.
- * Understanding Mig1 structure-function relationships is key.
- * Homologue identification in other yeast species aids comparative analysis.
Purpose of the Study:
- * To clone and characterize the *Kluyveromyces marxianus* Mig1 homologue (KmMig1).
- * To investigate the functional conservation and interactions of KmMig1 in *S. cerevisiae*.
- * To explore the structure-function dynamics of Mig1 across yeast species.
Main Methods:
- * Gene cloning and sequence analysis of *K. marxianus* MIG1.
- * Functional expression of KmMig1 in *S. cerevisiae*.
- * Promoter repression assays (SUC2, INU1) and protein interaction studies (Cyc8, Tup1, Snf1p kinase).
Main Results:
- * KmMig1 shares conserved motifs with other yeast Mig1 proteins, particularly within zinc fingers.
- * KmMig1 effectively represses the *SUC2* promoter in *S. cerevisiae*, dependent on Cyc8, Tup1, and C-terminal repeats.
- * KmMig1 is glucose-regulated in *S. cerevisiae*, and its interactions with *S. cerevisiae* proteins (Snf1p) are maintained.
- * KmMig1 represses the *INU1* gene in *K. marxianus*, analogous to *SUC2* repression in *S. cerevisiae*.
Conclusions:
- * KmMig1 exhibits significant functional conservation with *S. cerevisiae* Mig1p.
- * Conserved motifs outside the zinc fingers are functionally important for Mig1 activity and regulation.
- * The physiological role of Mig1 in glucose repression is conserved between *K. marxianus* and *S. cerevisiae*.