Promoter Function (promoter + function)

Distribution by Scientific Domains

Selected Abstracts


EVOLUTION, Issue 2 2002
Nadia A. Chuzhanova
Abstract Complexity analysis is capable of highlighting those gross evolutionary changes in gene promoter regions (loosely termed "promoter shuffling") that are undetectable by conventional DNA sequence alignment. Complexity analysis was therefore used here to identify the modular components (blocks) of the orthologous ,-globin gene promoter sequences of 22 vertebrate species, from zebrafish to humans. Considerable variation between the ,-globin gene promoters was apparent in terms of block presence/absence, copy number, and relative location. Some sequence blocks appear to be ubiquitous, whereas others are restricted to a specific taxon. Block similarities were also evident between the promoters of the paralogous human ,-like globin genes. It may be inferred that a wide variety of different mutational mechanisms have operated upon the ,-globin gene promoter over evolutionary time. Because these include gross changes such as deletion, duplication, amplification, elongation, contraction, and fusion, as well as the steady accumulation of single base-pair substitutions, it is clear that some redefinition of the term "promoter shuffling" is required. This notwithstanding, and as previously described for the vertebrate growth hormone gene promoter, the modular structure of the ,-globin promoter region and those of its paralogous counterparts have continually been rearranged into new combinations through the alteration, or shuffling, of preexisting blocks. Some of these changes may have had no influence on promoter function, but others could have altered either the level of gene expression or the responsiveness of the promoter to external stimuli. The comparative study of vertebrate ,-globin gene promoter regions described here confirms the generality of the phenomenon of sequence block shuffling and thus supports the view that it could have played an important role in the evolution of differential gene expression. [source]

Aly/,REF, a factor for mRNA transport, activates RH gene promoter function

FEBS JOURNAL, Issue 11 2005
Hiroshi Suganuma
The rhesus (Rh) blood group antigens are of considerable importance in transfusion medicine as well as in newborn or autoimmune hemolytic diseases due to their high antigenicity. We identified a major DNaseI hypersensitive site at the 5, flanking regions of both RHD and RHCE exon 1. A 34 bp fragment located at ,191 to ,158 from a translation start position, and containing the TCCCCTCCC sequence, was involved in enhancing promoter activity, which was assessed by luciferase reporter gene assay. A biotin-labelled 34 bp probe isolated an mRNA transporter protein, Aly/REF. The specific binding of Aly/REF to RH promoter in erythroid was confirmed by chromatin immunoprecipitation assay. The silencing of Aly/REF by siRNA reduced not only the RH promoter activity of the reporter gene but also transcription from the native genome. These facts provide second proof of Aly/REF as a transcription coactivator, initially identified as a coactivator for the TCR, enhancer function. Aly/REF might be a novel transcription cofactor for erythroid-specific genes. [source]

Functional analysis of the rat bile salt export pump gene promoter

FEBS JOURNAL, Issue 14 2002
Regulation by bile acids, drugs, endogenous compounds
The 5, flanking region of the bile salt export pump (Bsep) gene was systematically analysed to provide the basis for understanding the mechanisms which regulate Bsep transcription. In addition substrates and drugs were investigated for their ability to alter Bsep promoter activity. Bsep promoter function was restricted to hepatocyte derived HepG2 cells. The 5, deletional analysis revealed a biphasic shape of reporter gene activities, indicating a suppressive element between nucleotides ,800 and ,512. Two consensus sites for the farnesoid X receptor (FXR) were located at nucleotides ,473 and ,64. The latter was characterized as functionally active in bile acid-mediated feed-back regulation of Bsep transcription. Bsep promoter activity was reduced by rifampin and ,-estradiol. The anti-estrogen tamoxifen stimulated promoter activity. Dexamethasone, hydrocortisone and phenobarbital had no effect on Bsep promoter activity. In conclusion, the data suggest that transcriptional regulation of the Bsep gene can be modulated by a number of endogenous compounds and xenobiotics. FXR was a major regulatory factor, mediating bile acid feed-back stimulation of Bsep transcription. [source]

Probing bacterial nucleoid structure with optical tweezers

BIOESSAYS, Issue 3 2007
Charles J. Dorman
The H-NS protein is a major component of the nucleoid in Gram-negative bacterial cells. It is a global regulator of transcription that affects the expression of many genes, including virulence genes in pathogenic species. At a local level, it facilitates the formation of nucleoprotein structures that repress transcriptional promoter function. H-NS can form bridges between different DNA molecules or between different sections of the same molecule, allowing it to compact and impose structure on the nucleoid. A recent paper by Dame et al.1 reports new insights into H-NS-mediated DNA bridging that were obtained using an optical tweezers device. BioEssays 29: 212,216, 2007. 2007 Wiley Periodicals, Inc. [source]