Comparative analysis in three fungi reveals structurally and functionally conserved regions in the Mig1 repressor |
| |
Authors: | J.-P. Cassart J. ?stling H. Ronne J. Vandenhaute |
| |
Affiliation: | (1) Unité de Recherches en Biologie Moléculaire, Laboratoire de Génétique Moléculaire, Facultés Notre-Dame de la Paix, rue de Bruxelles, 61, B-5000 Namur, Belgium, BE;(2) Department of Medical Immunology and Microbiology, Uppsala University, Uppsala Biomedical Center, Box 582, S-75123 Uppsala, Sweden, SE;(3) Ludwig Institute for Cancer Research, Uppsala Branch, Uppsala Biomedical Center, Box 585, S-75124 Uppsala, Sweden, SE |
| |
Abstract: | The Mig1 repressor is a key effector in glucose repression in the yeast Saccharomyces cerevisiae. To gain further insights into structure-function relationships, we have now cloned the MIG1 homologue from the yeast Kluyveromyces marxianus. The amino acid sequence deduced from KmMIG1 differs significantly from ScMig1p outside the highly conserved zinc fingers. However, 12 discrete conserved motifs could be identified in a multiple alignment that also included the K. lactis Mig1p sequence. We further found that KmMig1p is fully functional when expressed in S. cerevisiae. First, it represses the SUC2 promoter almost as well as ScMig1p. This repression requires the Cyc8 and Tup1 proteins and is dependent on a C-terminal region comprising several conserved leucine-proline repeats. Second, KmMig1p is regulated by glucose in S. cerevisiae, and a KmMig1-VP16 hybrid activator is inhibited by the ScSnf1p kinase in the absence of glucose. This suggests that KmMig1p has retained the ability to interact with several S. cerevisiae proteins, and reinforces the notion that the conserved motifs are functionally important. Finally, we found that the physiological role of Mig1p also is conserved in K. marxianus, since KmMig1p represses INU1, the counterpart of SUC2 in this organism. Received: 16 October 1996 / Accepted: 19 February 1997 |
| |
Keywords: | MIG1 Glucose repression SNF1 Kluyveromyces marxianus INU1 |
本文献已被 SpringerLink 等数据库收录! |
|