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At least 721 records · Page 40Linked to original sources
PubMed1998

Promoter elements required for sugar-repression of the RAmy3D gene for alpha-amylase in rice.

There is increasing evidence showing that cereal alpha-amylase gene expression is controlled not only by the classical hormonal regulation, but also by feed-back sugar repression. We demonstrated by in situ hybridization that the sugar repression of rice alpha-amylase gene RAmy3D takes place in scutellar epithelium cells of callus-forming rice embryos. We also used a transient expression system to study the cis-acting elements involved in the sugar repression of the RAmy3D promoter activity. Site-directed mutagenesis of the 50-bp nucleotide sequence from -172 to -123 revealed that consensus sequences of G motif (TACGTA) and TATCCA T/C motif (GATA motif as its antisense sequence) are responsible for sugar repression. The promoter sequences required for sugar repression are reported and discussed.

Base Sequence↗
PubMed1990

Site-directed mutagenesis of a catabolite repression operator sequence in Bacillus subtilis.

Catabolite repression of the Bacillus subtilis alpha-amylase gene (amyE) involves an operator sequence located just downstream of the promoter (amyR), overlapping the transcription start site. Oligonucleotide site-directed mutagenesis of this sequence identified bases required for catabolite repression. Two mutations increased both the 2-fold symmetry of the operator and the repression ratio. Although many mutations reduced the repression ratio 3- to 11-fold, some also caused a 2-fold or greater increase in amylase production. Others caused hyperproduction without affecting catabolite repression. Homologous sequences in other catabolite-repressed B. subtilis promoters suggest a common regulatory site may be involved in catabolite repression.

Bacillus subtilis↗
PubMed1984

Influence of carbon catabolite repression on the G1 arrest of Saccharomyces cerevisiae MATa cells by alpha factor.

Cells of the yeast Saccharomyces cerevisiae of the a mating type were arrested at the G1 phase of the cell division cycle after treatment with alpha factor in a culture medium containing a high concentration (2%, w/v, or higher) of a catabolite-repressing sugar. In media containing either a lower concentration of sugar or a non-fermentable carbon source, the extent of G1 arrest induced by the pheromone was reduced or became undetectable. Under catabolite-derepressing conditions alpha factor was inactivated by a cells at a higher rate than that found in repressing media. These results indicate the existence of a close correlation between the action of alpha factor on a cells and conditions of catabolite repression or derepression. A joint mechanism of action of alpha factor and catabolite-repressing carbon sources on a cells is postulated.

Enzyme Repression↗
PubMed1981

A Pseudomonas aeruginosa mutant non-derepressible for orthophosphate-regulated proteins.

Using a rapid screening assay based on the hydrolysis of p-nitrophenylphosphorylcholine, we isolated several mutants of Pseudomonas aeruginosa deficient in the production of phospholipase C. One, designated strain A50N, was also markedly deficient in the synthesis of alkaline phosphatase and several unidentified extracellular proteins. Because strain A50N produces these proteins under conditions of derepression at levels equal to those produced by the parental strain PAO1 grown in medium containing excess phosphate, it appears to have a mutation in a genetic element involved in the derepression of phosphate-repressible proteins.

Alkaline Phosphatase↗
PubMed1975

Genes coding for the structure of the acid phosphatases in Saccharomyces cerevisiae.

The phoE locus, one of the loci in which mutations lack the activity for repressible acid phosphatase, was found to be the structural gene for the enzyme by examining the enzymic characteristics of repressible acid phosphatase activity using cell extracts prepared from the leaky phoE mutants, the PHOE revertants and the PHOE recombinants between the different phoE mutants. Other evidence which strongly suggests that the phoC locus is coding for the constitutive acid phosphatase was obtained by a similar investigation. Although the phoC and phoE loci are tightly linked, they were separable by meiotic recombination.

Acid Phosphatase↗