Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.7.48 (transcriptase)
 9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In humans, vocal tissue stiffness increases with age, suggesting a possible contribution of age-associated variations in vocal fold collagen turnover to voice senescence. The underlying mechanisms remain to be explored. With the use of reverse-transcriptase polymerase chain reaction (RT-PCR), collagen subtypes expressed in rat vocal folds were determined, and messenger RNA (mRNA) levels of collagens (types I, III, IV, and V), collagen-degrading proteinases (collagenase 3, gelatinase A and B), and tissue inhibitors of metalloproteinases (TIMP-1 to TIMP-4) were measured in vocal folds of neonatal, adult, and elderly rats. Collagens I, III-VIII, XV, XVII, and XVIII are abundantly expressed, whereas collagens II, IX, X, and XI are absent in rat vocal folds. Messenger RNA levels of collagens I, III, IV, and V and collagen-degrading proteinases in the vocal folds of the adult rats are significantly lower than those in the neonates. These mRNA levels show further decline in the vocal folds of the elderly rats, but only the decrease in mRNA levels of collagens I and V significantly differ from the adult levels. There are no marked age-related alterations in vocal fold levels of TIMP mRNAs, and the tissue variation in the gene expression of the aforementioned molecules is minute. Rat vocal folds display tissue-specific expression of collagen genes. Diminished gene expression for collagens and proteinases and unchanged gene expression for TIMPs indicate a slowdown in collagen turnover that may increase the cross-linking of collagen molecules. This observation may explain in part the stiffness that occurs with aging in human vocal folds.
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PMID:Senescent expression of genes coding collagens, collagen-degrading metalloproteinases, and tissue inhibitors of metalloproteinases in rat vocal folds: comparison with skin and lungs. 1128 85

Interleukin-1 is considered a central mediator of cartilage loss in osteoarthritis in several species, however an equine recombinant form of this cytokine is not readily available for in vitro use in equine osteoarthritis research. Equine recombinant interleukin-1beta was cloned and expressed and its effects on the expression and activity of selected chondrocytic proteins implicated in cartilage matrix degradation were characterized. Reverse transcriptase polymerase chain reaction methods were used to amplify the entire coding region of the equine IL-1beta mRNA, which was cloned into an expression vector, expressed in E. coli, and purified using a Ni2+ chromatographic method. The effects of the recombinant peptide on chondrocyte gene expression were determined by Northern blotting using RNA from equine chondrocyte cultures hybridized to probes for matrix metalloproteinases (MMP 1, MMP 3, MMP 13), tissue inhibitor of matrix metalloproteinases 1 (TIMP 1) and cyclooxygenase 2 (COX 2). Effects on selected mediators of cartilage degradation (nitrite concentrations and MMP activity) were determined using conditioned medium from reIL-1beta-treated equine cartilage explant cultures. A recombinant peptide of approximately 21 kd was obtained. Northern blotting analyses revealed a marked up-regulation of expression of all MMPs, TIMP 1, and COX 2 in mRNA from treated chondrocytes. Furthermore, cartilage explants exposed to reIL-1beta had augmented collagenase/gelatinase and stromelysin activities as well as increased concentration of nitrite in conditioned media. The development of a biologically active, species-specific IL-1beta provides a valuable tool in the study of osteoarthritis pathophysiology and its treatment in horses.
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PMID:Recombinant equine interleukin-1beta induces putative mediators of articular cartilage degradation in equine chondrocytes. 1185 44

In contrast to adult cutaneous wounds, early fetal wounds heal scarlessly. Fetal rat skin transitions from scarless repair to healing, with scar formation between days 16.5 (E16) and 18.5 (E18) of gestation. Term gestation is 21.5 days. The composition of the extracellular matrix in fetal skin and wounds differs from that of the adult. Matrix metalloproteinases (MMPs) and their tissue-derived inhibitors (TIMPs) determine the architecture of the extracellular matrix. The authors hypothesized that differential expression of MMPs and TIMPs occurs during the ontogenetic transition to scar-forming repair in fetal skin and wounds. Full-thickness, excisional wounds (2 mm) were created on the dorsum of E16 (n = 42 fetuses) and E19 fetal rats (n = 42 fetuses). Wounds were harvested at 24, 48, and 72 hours. Nonwounded skin from littermates was also harvested as controls. Six E16 and E19 wounds were fixed 72 hours after injury, stained with hematoxylin and eosin, and examined by light microscopy. RNA was isolated from the remaining wounds and skin, and a reduced-cycle, primer-specific, reverse-transcriptase polymerase chain reaction was performed to semiquantitatively determine relative gene expression of MMP-1, MMP-2, MMP-7, MMP-9, and MMP-14 and of TIMP-1, TIMP-2, and TIMP-3. Significance was determined by unpaired two-tailed t test (p < 0.05) and analysis of variance. In both E16 and E19 wounds, reepithelialization was complete by 72 hours. E16 wounds healed scarlessly, whereas E19 wounds healed with scar. During late gestation, skin expression of MMP-1 and MMP-14 (membrane type-1 MMP) doubled, whereas MMP-2 expression increased nearly 50-fold. Levels of MMP-7 and MMP-9 were unchanged in developing skin. As for the TIMPs, skin expression of TIMP-2 increased more than four-fold, whereas TIMP-1 and TIMP-3 expression was unchanged. In both scarless and scarring wounds, up-regulation of MMP-1 and MMP-9 occurred. However, the maximal increase in MMP-1 and MMP-9 expression occurred much more rapidly and was much greater in the scarless E16 wounds (28-fold versus 23-fold for MMP-1 and 18-fold versus nine-fold for MMP-9). Unchanged in scarless wounds, MMP-2 levels decreased more than three-fold in scarring wounds. MMP-14 (membrane type-1 MMP) expression increased three-fold in scarless wounds but was unchanged in scarring wounds. In contrast, TIMP-1 and TIMP-3 expression in E19 scarring wounds increased six-fold and four-fold, respectively. MMP-7 and TIMP-2 expression did not change in response to injury. E16 scarless wounds have greater MMP relative to TIMP expression than E19 scarring wounds. This favors extracellular matrix turnover, facilitates migration of fetal cells, and promotes scarless repair.
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PMID:Scarless fetal wounds are associated with an increased matrix metalloproteinase-to-tissue-derived inhibitor of metalloproteinase ratio. 1279 70