Journal article
Extragenic pleiotropic mutations that repress glycosyl hydrolase expression in the hyperthermophilic archaeon Sulfolobus solfataricus
Genetics (Austin), Vol.152(4), pp.1353-1361
08/1999
Handle:
https://hdl.handle.net/2376/113783
PMCID: PMC1460713
PMID: 10430566
Abstract
The hyperthermophilic archaeon Sulfolobus solfataricus employs a catabolite repression-like regulatory system to control enzymes involved in carbon and energy metabolism. To better understand the basis of this system, spontaneous glycosyl hydrolase mutants were isolated using a genetic screen for mutations, which reduced expression of the lacS gene. The specific activities of three glycosyl hydrolases, including an alpha-glucosidase (malA), a beta-glycosidase (lacS), and the major secreted alpha-amylase, were measured in the mutant strains using enzyme activity assays, Western blot analysis, and Northern blot analysis. On the basis of these results the mutants were divided into two classes. Group I mutants exhibited a pleiotropic defect in glycosyl hydrolase expression, while a single group II mutant was altered only in lacS expression. PCR, Southern blot analysis, comparative heterologous expression in Escherichia coli, and DNA sequence analysis excluded cis-acting mutations as the explanation for reduced lacS expression in group I mutants. In contrast lacS and flanking sequences were deleted in the group II mutant. Revertants were isolated from group I mutants using a lacS-specific screen and selection. These revertants were pleiotropic and restored glycosyl hydrolase activity either partially or completely to wild-type levels as indicated by enzyme assays and Western blots. The lacS mutation in the group II mutant, however, was nonrevertible. The existence of group I mutants and their revertants reveals the presence of a trans-acting transcriptional regulatory system for glycosyl hydrolase expression.
Metrics
9 Record Views
Details
- Title
- Extragenic pleiotropic mutations that repress glycosyl hydrolase expression in the hyperthermophilic archaeon Sulfolobus solfataricus
- Creators
- C Haseltine - George Beadle Center for Genetics, School of Biological Sciences, University of Nebraska, Lincoln, Nebraska 68588-0666, USAR Montalvo-Rodriguez - George Beadle Center for Genetics, School of Biological Sciences, University of Nebraska, Lincoln, Nebraska 68588-0666, USAA Carl - George Beadle Center for Genetics, School of Biological Sciences, University of Nebraska, Lincoln, Nebraska 68588-0666, USAE Bini - George Beadle Center for Genetics, School of Biological Sciences, University of Nebraska, Lincoln, Nebraska 68588-0666, USAP Blum - George Beadle Center for Genetics, School of Biological Sciences, University of Nebraska, Lincoln, Nebraska 68588-0666, USA
- Publication Details
- Genetics (Austin), Vol.152(4), pp.1353-1361
- Academic Unit
- Molecular Biosciences, School of
- Identifiers
- 99900547902401842
- Language
- English
- Resource Type
- Journal article