Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.7.49 (reverse transcriptase)
 31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hypertrophic scarring is a skin disorder that occurs after wounding and thermal injury. There is accumulating evidence that immunologic processes such as infiltration of activated T lymphocytes and altered cytokine production may play a role in the formation of hypertrophic scars. Interleukin-15, a cytokine identified as a T cell growth factor, also acts as a chemoattractant for T cells and has pro-inflammatory properties. We investigated the expression and the role of this cytokine in hypertrophic scarring. IL-15 expression was compared in skin biopsies of hypertrophic scars (HS) both in active (AHS) and in remission (RHS) phases, in normotrophic scars (NTS) and in normal skin using reverse transcriptase-polymerase chain reaction and immunohistochemistry. IL-15 expression in HS was significantly higher than in NTS or normal skin. Furthermore, AHS expressed higher levels of IL-15 than RHS. Immunohistologic analysis of AHS samples showed strong IL-15 immunoreactivity in keratinocytes and Langerhans cells in the epidermis and in macrophages, fibroblasts, and dermal dendritic cells in the dermis. High levels of IL-15 expression in AHS correlated with abundant infiltration of activated CD3+ cells. Ex vivo experiments indicate that IL-15 can sustain the proliferative response of T cells derived from AHS but not from RHS and NTS. In addition, IL-15 prevents both cytokine deprivation and activation-induced apoptosis of T cells derived from AHS. Taken together, these results suggest that IL-15 can be involved in the recruitment, proliferation, and apoptosis inhibition of T cells in AHS. The findings that the evolution from an AHS to a RHS is associated with a decrease in IL15 expression, and with a loss of IL-15 responsiveness in ex vivo-cultured T cells, indicate that this cytokine plays an important role in the biology of pathologic scar formation.
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PMID:Expression and role of IL-15 in post-burn hypertrophic scars. 1046 10

Homologs of quorum-sensing luxR and luxI regulatory genes, avsR and avsI, were identified in Agrobacterium vitis strain F2/5. Compared to other LuxI proteins from related species, the deduced AvsI shows the greatest identity to SinI (71%) from Sinorhizobium meliloti Rm1021. AvsR possesses characteristic autoinducer binding and helix-turn-helix DNA binding domains and shares a high level of identity with SinR (38%) from Rm1021. Site-directed mutagenesis of avsR and avsI was performed, and both genes are essential for hypersensitive-like response (HR) and necrosis. Two hypothetical proteins (ORF1 and ORF2) that are positioned downstream of avsR-avsI are also essential for the phenotypes. Profiles of N-acyl-homoserine lactones (AHLs) isolated from the wild type and mutants revealed that disruption of avsI, ORF1, or ORF2 abolished the production of long-chain AHLs. Disruption of avsR reduces long-chain AHLs. Expression of a cloned avsI gene in A. tumefaciens strain NT1 resulted in synthesis of long-chain AHLs. The necrosis and HR phenotypes of the avsI and avsR mutants were fully complemented with cloned avsI. The addition of synthetic AHLs (C(16:1) and 3-O-C(16:1)) complemented grape necrosis in the avsR, avsI, ORF1, and ORF2 mutants. It was determined by reverse transcriptase PCR that the expression level of avsI is regulated by avsR but not by aviR or avhR, two other luxR homologs which were previously shown to be associated with induction of a tobacco hypersensitive response and grape necrosis. We further verified that avsR regulates avsI by measuring the expression of an avsI::lacZ fusion construct.
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PMID:Regulation of long-chain N-acyl-homoserine lactones in Agrobacterium vitis. 1651 47

P. aeruginosa living in biofilm populations sends out diffusive signalling molecules, called autoinducers, for example acylated homoserine lactone (AHL) or the P. aeruginosa quinolone signal (PQS). So far, two quorum-sensing systems, LasR and VsmR, have been identified in P. aeruginosa, both of which are required for all virulence determinants. The expression of specific genes involved in quorum-sensing regulatory mechanisms has been analysed with molecular biology methods. Real-time quantitative PCR is a highly sensitive and powerful technique for quantification of nucleic acids. Expression of the genes vsmR, lasI, and PA4296 was studied by use of reverse transcriptase and subsequent quantitative real-time PCR of the cDNAs. In parallel, expression of ribosomal 16S rRNA, used as a housekeeping gene that was constitutively expressed in all analyses, was also monitored. Biofilm was compared with planktonic bacteria, and in contrast to vsmR and Pa4296, the lasI gene was found to be down-regulated in biofilm. Extended experiments were run with synthetic signal molecules inducing regulated processes in bacterial populations. It was shown that the genes under investigation were up-regulated in mature biofilm in the presence of the signal molecule N-(3-oxododecanoyl)-L-homoserine lactone.
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PMID:Use of quantitative real-time RT-PCR to analyse the expression of some quorum-sensing regulated genes in Pseudomonas aeruginosa. 1713 Nov 12