Transcription (biology)

About: Transcription (biology) is a research topic. Over the lifetime, 56532 publications have been published within this topic receiving 2952782 citations. The topic is also known as: genetic transcription & transcription, genetic.

Persistence of HIV-1 transcription in peripheral-blood mononuclear cells in patients receiving potent antiretroviral therapy

Abstract: Background and Methods Although potent antiretroviral therapy can control infection with human immunodeficiency virus type 1 (HIV-1), a long-lived reservoir of infectious virus persists in CD4+ T cells. We investigated this viral reservoir by measuring the levels of cell-associated viral DNA and messenger RNA (mRNA) that are essential for HIV-1 replication. Approximately every 6 months, we obtained samples of peripheral-blood mononuclear cells from five men with long-standing HIV-1 infection who had had undetectable levels of plasma HIV-1 RNA for 20 months or more during treatment with potent antiretroviral drugs. Results Before treatment, plasma levels of HIV-1 RNA correlated with the levels of cell-associated unintegrated HIV-1 DNA and unspliced viral mRNA. After treatment, plasma levels of HIV-1 RNA fell by more than 2.7 log to undetectable levels. The decrease in cell-associated integrated and unintegrated HIV-1 DNA and mRNA occurred in two phases. The first phase occurred during the initial 500 days ...

Analysis of p53-regulated gene expression patterns using oligonucleotide arrays

Abstract: Oligonucleotide microarrays were employed to quantitate mRNA levels from a large number of genes regulated by the p53 transcription factor. Responses to DNA damage and to zinc-inducible p53 were compared for their transcription patterns in cell culture. A cluster analysis of these data demonstrates that genes induced by gamma radiation, UV radiation, and the zinc-induced p53 form distinct sets and subsets with a few genes in common to all these treatments. Cell type- or cell line-specific p53 responses were detected. When p53 proteins were induced with zinc, the kinetics of induction or repression of mRNAs from p53-responsive genes fell into eight distinct classes, five different kinetics of induction, and three different kinetics of repression. In addition, low levels of p53 in a cell induced or repressed only a subset of genes observed at higher p53 levels. The results of this study demonstrate that the nature of the p53 response in diverse mRNA species depends on the levels of p53 protein in a cell, the type of inducing agent or event, and the cell type employed. Of 6000 genes examined for p53 regulatory responses, 107 induced and 54 repressed genes fell into categories of apoptosis and growth arrest, cytoskeletal functions, growth factors and their inhibitors, extracellular matrix, and adhesion genes.

Synergistic activation of transcription by CBP and p53

Abstract: The tumour suppressor p53 is a transcriptional regulator whose ability to inhibit cell growth is dependent upon its transactivation function. Here we demonstrate that the transcription factor CBP, which is also implicated in cell proliferation and differentiation, acts as a p53 coactivator and potentiates its transcriptional activity. The amino-terminal activation domain of p53 interacts with the carboxy-terminal portion of the CBP protein both in vitro and in vivo. In transfected SaoS-2 cells, CBP potentiates activation of the mdm-2 gene by p53 and, reciprocally, p53 potentiates activation of a Gal4-responsive target gene by a Gal4(1-147)-CBP(1678-2441) fusion protein. A double point mutation that destroys the transactivation function of p53 also abolishes its binding to CBP and its synergistic function with CBP. The ability of p53 to interact physically and functionally with a coactivator (CBP) that has histone acetyltransferase activity and with components (TAFs) of the general transcription machinery indicates that it may have different functions in a multistep activation pathway.

RNA modifications modulate gene expression during development

Abstract: RNA modifications have recently emerged as critical posttranscriptional regulators of gene expression programs. They affect diverse eukaryotic biological processes, and the correct deposition of many of these modifications is required for normal development. Messenger RNA (mRNA) modifications regulate various aspects of mRNA metabolism. For example, N6-methyladenosine (m6A) affects the translation and stability of the modified transcripts, thus providing a mechanism to coordinate the regulation of groups of transcripts during cell state maintenance and transition. Similarly, some modifications in transfer RNAs are essential for RNA structure and function. Others are deposited in response to external cues and adapt global protein synthesis and gene-specific translational accordingly and thereby facilitate proper development.

A glucose-responsive transcription factor that regulates carbohydrate metabolism in the liver

Abstract: Carbohydrates mediate their conversion to triglycerides in the liver by promoting both rapid posttranslational activation of rate-limiting glycolytic and lipogenic enzymes and transcriptional induction of the genes encoding many of these same enzymes. The mechanism by which elevated carbohydrate levels affect transcription of these genes remains unknown. Here we report the purification and identification of a transcription factor that recognizes the carbohydrate response element (ChRE) within the promoter of the L-type pyruvate kinase (LPK) gene. The DNA-binding activity of this ChRE-binding protein (ChREBP) in rat livers is specifically induced by a high carbohydrate diet. ChREBP's DNA-binding specificity in vitro precisely correlates with promoter activity in vivo. Furthermore, forced ChREBP overexpression in primary hepatocytes activates transcription from the L-type Pyruvate kinase promoter in response to high glucose levels. The DNA-binding activity of ChREBP can be modulated in vitro by means of changes in its phosphorylation state, suggesting a possible mode of glucose-responsive regulation. ChREBP is likely critical for the optimal long-term storage of excess carbohydrates as fats, and may contribute to the imbalance between nutrient utilization and storage characteristic of obesity.