Search results for "Expression"

Fine analysis of the chromatin structure of the yeast SUC2 gene and of its changes upon derepression. Comparison between the chromosomal and plasmid-…

1987

Micrococcal nuclease digestion has been used to investigate some fine details of the chromatin structure of the yeast SUC2 gene for invertase. Precisely positioned nucleosomes have been found on a 2 kb sequence from the 3' non-coding region, and four nucleosomes also seem to occupy fixed positions on the 5' flank. Eleven nucleosomes lie on the coding region, although their positioning is not as precise as in the flanks. When the gene is derepressed, these latter nucleosomes adopt a more open conformation and so do two of the nucleosomes positioned on the 5' flank. A dramatic change occurs in the 3' flank, whose involvement in the structural transitions of chromatin upon gene activation is p…

Epigenetic regulation of stemness maintenance in the neurogenic niches

2015

In the adult mouse brain, the subventricular zone lining the lateral ventricles and the subgranular zone in the dentate gyrus of the hippocampus are two zones that contain neural stem cells (NSCs) with the capacity to give rise to neurons and glia during the entire life of the animal. Spatial and temporal regulation of gene expression in the NSCs population is established and maintained by the coordinated interaction between transcription factors and epigenetic regulators which control stem cell fate. Epigenetic mechanisms are heritable alterations in genome function that do not involve changes in DNA sequence itself but that modulate gene expression, acting as mediators between the environ…

2013

MicroRNAs of the miR-302 cluster are involved in early embryonic development and somatic cell reprogramming. Expression of the miR-302 gene is regulated by the binding of the pluripotency factors Oct4, Sox2 and Nanog to the miR-302 promoter. The specific expression pattern of the miR-302 gene suggested that additional transcription factors might be involved in its regulation. Here, we show that the miR-302 promoter is a direct target of the Wnt/β-catenin signaling pathway. We found that the miR-302 promoter contains three different functional Tcf/Lef binding sites. Two of the three sites were located within the cluster of Oct4/Sox2/Nanog binding sites and were essential for Wnt/β-catenin-me…

The Yeast External Invertase as a Reporter to Study Regulation ofCandida Albicans Promoter Sequences inSaccharomyces Cerevisiae

2008

The conservation and diversity of ascidian cells and molecules involved in the inflammatory reaction: The Ciona robusta model

2021

Ascidians are marine invertebrate chordates belonging to the earliest branch (Tunicata) in the chordate phylum, therefore, they are of interest for studying the evolution of immune systems. Due to the known genome, the non-colonial Ciona robusta, previously considered to be C. intestinalis type A, is a model species for the study of inflammatory response. The internal defense of ascidians mainly relies on hemocytes circulating in the hemolymph and pharynx. Hemocytes can be in vivo challenged by LPS injection and various granulocyte and vacuolated cell populations differentiated to produce and release inflammatory factors. Molecular biology and gene expression studies revealed complex defens…

Functional regulation of HIF-1α under normoxia--is there more than post-translational regulation?

2011

The hypoxia-inducible factor-1 (HIF-1) is an oxygen-regulated transcriptional activator playing a pivotal role in mammalian physiology and disease pathogenesis, e.g., HIF-1 is indispensable in a broad range of developmental stages in different tumors. Its post-translational regulation via PHDs under the influence of hypoxia is widely investigated and accepted. Different non-hypoxic stimuli such as lipopolysaccharides (LPS), thrombin, and angiotensin II (Ang II), have been proven to enhance HIF-1 levels through activation of regulative mechanisms distinct from protein stabilization. Some of these stimuli specifically regulate HIF-1α at the transcriptional, post-transcriptional, or translatio…

T47-D Cells and Type V Collagen: A Model for the Study of Apoptotic Gene Expression by Breast Cancer Cells

2003

We have previously reported that type V collagen is a poorly adhesive, anti-proliferative and motility-inhibitory substrate for the 8701-BC breast cancer cell line, which also triggers DNA fragmentation and impairs survival of the same cell line. In the present work we have extended to other breast cancer cell lines (T47-D, MDA-MB231, Hs578T) our investigation of type V collagen influence on the DNA status and cell survival, also examining whether adhesion and growth of cells on this collagen substrate could exert some effect on the expression level of selected apoptosis-related genes. We report here that, among the cell lines tested, only T47-D is responsive to the death-promoting influenc…

Complex Contribution of the 3′-Untranslated Region to the Expressional Regulation of the Human Inducible Nitric-oxide Synthase Gene

2000

Cytokine stimulation of human DLD-1 cells resulted in a marked expression of nitric-oxide synthase (NOS) II mRNA and protein accompanied by only a moderate increase in transcriptional activity. Also, there was a basal transcription of the NOS II gene, which did not result in measurable NOS II expression. The 3′-untranslated region (3′-UTR) of the NOS II mRNA contains four AUUUA motifs and one AUUUUA motif, known to destabilize the mRNAs of proto-oncogenes, nuclear transcription factors, and cytokines. Luciferase reporter gene constructs containing the NOS II 3′-UTR showed a significantly reduced luciferase activity. The embryonic lethal abnormal vision (ELAV)-like protein HuR was found to b…

The transcriptional inhibitor thiolutin blocks mRNA degradation in yeast.

2007

Thiolutin is commonly used as a general inhibitor of transcription in yeast. It has been used to calculate mRNA decay rates by stopping the transcription and then determining the relative abundance of individual mRNAs at different times after inhibition. We report here that thiolutin is also an inhibitor of mRNA degradation, and thus its use can lead to miscalculations of mRNA half-lives. The inhibition of mRNA decay seems to affect the mRNA degradation pathway without impeding poly(A) shortening, given that the decay rate of total poly(A) amount is not reduced by thiolutin. Moreover, the thiolutin-dependent inhibition of mRNA degradation has variable effects on different functional groups …

Genomic-Wide Methods to Evaluate Transcription Rates in Yeast

2011

Gene transcription is a dynamic process in which the desired amount of an mRNA is obtained by the equilibrium between its transcription (TR) and degradation (DR) rates. The control mechanism at the RNA polymerase level primarily causes changes in TR. Despite their importance, TRs have been rarely measured. In the yeast Saccharomyces cerevisiae, we have implemented two techniques to evaluate TRs: run-on and chromatin immunoprecipitation of RNA polymerase II. These techniques allow the discrimination of the relative importance of TR and DR in gene regulation for the first time in a eukaryote.