Regulation of gene expression

About: Regulation of gene expression is a research topic. Over the lifetime, 85456 publications have been published within this topic receiving 5832845 citations. The topic is also known as: GO:0010468 & gene expression regulation.

Human growth hormone as a reporter gene in regulation studies employing transient gene expression.

Abstract: The human growth hormone (hGH) transient assay system described here is based on the expression of hGH directed by cells transfected with hGH fusion genes. Levels of secreted hGH in the medium, measured by a simple radioimmunoassay, are proportional to both levels of cytoplasmic hGH mRNA and the amount of transfected DNA. The system is extremely sensitive, easy to perform, and is qualitatively different from other transient expression systems in that the medium is assayed and the cells themselves are not destroyed. The hGH transient assay system is appropriate for analyses of regulation of gene expression and was utilized here to investigate the effect of the simian virus 40 enhancer on the herpes simplex virus thymidine kinase promoter and the effect of zinc on the mouse metallothionein-I promoter. The expression of hGH can also be used as an internal control to monitor transfection efficiency along with any other transient expression system. All cell types tested thus far (including AtT-20, CV-1, GC, GH4, JEG, L, and primary pituitary cells) were able to secrete hGH into the medium.

Activation of transcription by two factors that bind promoter and enhancer sequences of the human metallothionein gene and SV40

Abstract: Genetic analysis of eukaryotic transcriptional promoters has revealed that protein-coding genes often contain a complex array of cis-control elements consisting of upstream activator sequences and enhancer elements1–5. The metallothionein genes provide a useful example for dissecting the action of multiple interspersed control elements that govern both basal level and regulated expression in animal cells6–8. The human metallothionein (hMTIIA) promoter has been analysed in detail and found to contain no less than five distinct control elements in the 5' flanking regions of the gene that mediate specificity and regulation of transcription9,10 (Fig. 1). These different control elements can be functionally subdivided into two categories: basal and induced elements. There are several distinct basal recognition sequences, which include a TATA-box, a GC-box, and at least two basal level enhancer (BLE) sequences, that function like classical enhancer elements10–12. The hMTIIA gene also responds to induction by heavy metals and by steroid hormones through the action of metal regulatory elements (MRE) and glucocorticoid responsive elements (GRE)9. Here we report the identification of two cellular DNA-binding proteins that interact selectively with sequences governing the basal level expression of hMTIIA. One of these factors is a novel activator protein (API) that interacts with sequences in the BLE of hMTIIA and also binds to a site within the 72-base pair (bp) repeats of the simian virus 40 (SV40) enhancer region. The second protein has been purified to homogeneity and shown to be transcription factor Sp1 which recognizes and binds to a single GC-box element within the hMTIIA promoter.