Search results for "Transferase"

A differential role of CREB phosphorylation in cAMP-inducible gene expression in the rat pineal

2000

In the rat pineal gland cAMP mediates nocturnal induction of the enzyme arylalkylamine N-acetyltransferase (AA-NAT) as well as of transcription factors such as inducible cAMP early repressor (ICER), Fos-related antigen-2 (Fra-2) and JunB. Cyclic AMP stimulates the phosphorylation of the DNA binding protein cAMP response element binding protein (CREB). While cAMP-induced CREB phosphorylation appears to be a prerequisite for AA-NAT and ICER gene expression, it is not known whether CREB phosphorylation accounts for the full cAMP response of the two genes. Furthermore, the significance of CREB phosphorylation in cAMP-activated Fra-2 and JunB transcription is unknown. In the present in vitro stu…

Expression of a reporter gene is reduced by a ribozyme in transgenic plants

1994

A chimeric gene encoding a ribozyme under the control of the cauliflower mosaic virus (CaMV) 35S promoter was introduced into transgenic tobacco plants. In vivo activity of this ribozyme, which was designed to cleave npt mRNA, was previously demonstrated by transient expression assays in plant protoplasts. The ribozyme gene was transferred into transgenic tobacco plants expressing an rbcS-npt chimeric gene as an indicator. Five double transformants out of sixteen exhibited a reduction in the amount of active NPT enzyme. To measure the amount of ribozyme produced, in the absence of its target, the ribozyme and target genes were separated by genetic segregation. The steady-state concentration…

Helicobacter pylori gamma-glutamyl transpeptidase and vacuolating cytotoxin promote gastric persistence and immune tolerance

2013

Infection with the gastric bacterial pathogen Helicobacter pylori is typically contracted in early childhood and often persists for decades. The immunomodulatory properties of H. pylori that allow it to colonize humans persistently are believed to also account for H. pylori ’s protective effects against allergic and chronic inflammatory diseases. H. pylori infection efficiently reprograms dendritic cells (DCs) toward a tolerogenic phenotype and induces regulatory T cells (Tregs) with highly suppressive activity in models of allergen-induced asthma. We show here that two H. pylori virulence determinants, the γ-glutamyl transpeptidase GGT and the vacuolating cytotoxin VacA, contribute critic…

A Trial of a Transglutaminase 2 Inhibitor in Celiac Disease. Reply.

2021

Retrotransposon silencing and telomere integrity in somatic cells of Drosophila depends on the cytosine-5 methyltransferase DNMT2

2009

Here we show that the cytosine-5 methyltransferase DNMT2 controls retrotransposon silencing in Drosophila somatic cells. In Drosophila, significant DNMT2-dependent DNA methylation occurs during early embryogenesis. Suppression of white gene silencing by Mt2 (Dnmt2) null mutations in variegated P[w(+)] element insertions identified functional targets of DNMT2. The enzyme controls DNA methylation at retrotransposons in early embryos and initiates histone H4K20 trimethylation catalyzed by the SUV4-20 methyltransferase. In somatic cells, loss of DNMT2 eliminates H4K20 trimethylation at retrotransposons and impairs maintenance of retrotransposon silencing. In Dnmt2 and Suv4-20 null genotypes, re…

P sequences ofDrosophilla Subobscuralack exon 3 and may encode a 66 kd repressor-like protein

1991

Abstract Several P homologous sequences have been cloned and sequenced from Drosophila subobscura. These sequences are located at the 85DE region of the O chromosome and at least three of them are organized in tandem. We have identified four copies which exhibit strong similarity between them. All of the isolated elements are truncated at the 5' and 3' ends. They have lost the inverted terminal repeats and exon 3, but maintain exons 0, 1 and 2. They are transcribed producing a polyadenylated RNA. The structure of these transcripts suggests that they are able to encode a 66 kd repressor-like protein, but not a functional transposase. We ask about the biological role of a potential repressor …

Mycobacterium tuberculosis secretory proteins downregulate T cell activation by interfering with proximal and downstream T cell signalling events

2015

Background Mycobacterium tuberculosis (M. tuberculosis) modulates host immune response, mainly T cell responses for its own survival leading to disease or latent infection. The molecules and mechanisms utilized to accomplish immune subversion by M. tuberculosis are not fully understood. Understanding the molecular mechanism of T cell response to M. tuberculosis is important for development of efficacious vaccine against TB. Methods Here, we investigated effect of M. tuberculosis antigens Ag85A and ESAT-6 on T cell signalling events in CD3/CD28 induced Peripheral blood mononuclear cells (PBMCs) of PPD+ve healthy individuals and pulmonary TB patients. We studied CD3 induced intracellular calc…

Binding of PTEN to specific PDZ domains contributes to PTEN protein stability and phosphorylation by microtubule-associated serine/threonine kinases

2005

The tumor suppressor phosphatase PTEN is a key regulator of cell growth and apoptosis that interacts with PDZ domains from regulatory proteins, including MAGI-1/2/3, hDlg, and MAST205. Here we identified novel PTEN-binding PDZ domains within the MAST205-related proteins, syntrophin-associated serine/threonine kinase and MAST3, characterized the regions of PTEN involved in its interaction with distinctive PDZ domains, and analyzed the functional consequences on PTEN of PDZ domain binding. Using a panel of PTEN mutations, as well as PTEN chimeras containing distinct domains of the related protein TPTE, we found that the PTP and C2 domains of PTEN do not affect PDZ domain binding and that the …

Functional coupling of nitric oxide synthase and soluble guanylyl cyclase in controlling catecholamine secretion from bovine chromaffin cells

1997

This study was designed to evaluate whether the enzymes of the nitric oxide/cyclic-GMP pathway, nitric oxide synthase and soluble guanylyl cyclase, are functionally coupled in controlling catecholamine secretion in primary cultures of bovine chromaffin cells. In immunocytochemical studies, 80-85% of the tyrosine hydroxylase-positive chromaffin cells also possessed phenylethanolamine-N-methyltransferase, f1p4cating their capability to synthesize epinephrine. Immunoreactivity for neuronal-type nitric oxide synthase was found in over 90% of all chromaffin cells. Reverse transcription-polymerase chain reaction also demonstrated neuronal-type nitric oxide synthase messenger RNA. Immunoreactivity…

NMR structure of a non-conjugatable, ADP-ribosylation associated, ubiquitin-like domain from Tetrahymena thermophila polyubiquitin locus.

2019

Abstract Background Ubiquitin-like domains (UbLs), in addition to being post-translationally conjugated to the target through the E1-E2-E3 enzymatic cascade, can be translated as a part of the protein they ought to regulate. As integral UbLs coexist with the rest of the protein, their structural properties can differ from canonical ubiquitin, depending on the protein context and how they interact with it. In this work, we investigate T.th-ubl5, a UbL present in a polyubiquitin locus of Tetrahymena thermophila, which is integral to an ADP-ribosyl transferase protein. Only one other co-occurrence of these two domains within the same protein has been reported. Methods NMR, multiple sequence al…