Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.7.49 (reverse transcriptase)
31,746 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Proteolytic activity present in the excreted/secreted (ES) material of newly excysted juvenile (NEJ) Fasciola hepatica was biochemically analyzed. By gelatin substrate SDS-PAGE, only one region of activity was observed in the NEJ ES material at a molecular mass of 29 kDa. Both the secreted cathepsin L from adult fluke and the 29-kDa proteolytic activity of NEJ ES show a common pH optimum of 7.5, a cysteine protease inhibition profile, and preference for the N-benzyloxycarbonyl (Z)-Phe-Arg-NHMec fluorogenic substrate over Z-Arg-Arg-NHMec and Z-Arg-NHMec. In vitro analysis revealed that the NEJ protease activity digested sheep immunoglobulin heavy chain and bovine serum albumin but not bovine hemoglobin. Amino-terminal protein sequence analysis of the 29-kDa NEJ protease band revealed two sequences with homology to the cathepsin B family of proteases. Using degenerate oligonucleotides designed from the N-terminal sequence, reverse transcriptase polymerase chain reaction with NEJ RNA amplified a cDNA sequence encoding the first 236 amino acids of mature cathepsin B. Using this cDNA fragment an overlapping cDNA was isolated from a LambadaZAP cDNA library constructed with poly(A)+ RNA from immature 5-week-old liver fluke. Together with the N-terminal sequence, these cDNAs predict a mature cathepsin B sequence of 254 amino acids which shows 48-51% sequence identity to mammalian and Schistosoma mansoni cathepsin B. We conclude that, in contrast to the major proteases released by adult fluke, the major secreted protease of NEJ of F. hepatica is of the cathepsin B class.
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PMID:Fasciola hepatica: characterization and cloning of the major cathepsin B protease secreted by newly excysted juvenile liver fluke. 953 62

Identification of the genes that are specifically expressed in either tumor or normal tissue is important for understanding cancer biology. Using differential displays, we obtained one gene which was specifically expressed in normal tissue but is only rarely expressed in carcinoma tissue of the human esophagus. The sequence of this gene was identical with cystatin B, known to be one of the cysteine-proteinase inhibitors, mainly inhibiting cathepsin L. There is little information on the clinical significance of cystatin B expression in human esophageal carcinoma. We thus studied the mRNA expression of cystatin B in 45 tumor/normal pair specimens of the esophagus, using the semi-quantitative reverse transcriptase polymerase chain reaction technique. The expression of cystatin B in tumor tissue was found to be markedly decreased compared with that of the corresponding normal tissue. The cases with a tumor/normal ratio of less than 0.5 showed high frequency of lymph-node metastasis and more advanced clinical stage as compared with those whose tumor/normal ratio was equal to or more than 0.5. The decreased expression of cystatin B protein in carcinoma tissue was confirmed by immunohistochemical staining. Our study suggests that reduced expression of cystatin B in esophageal-carcinoma tissue is associated with lymph-node metastasis and may therefore prove to be a useful marker for predicting the biologic aggressiveness of human esophageal carcinoma.
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PMID:Identification of cystatin B in human esophageal carcinoma, using differential displays in which the gene expression is related to lymph-node metastasis. 958 33

To examine whether proteases are possibly involved in cellular migration and/or spermiation when developing germ cells translocate across the seminiferous epithelium during spermatogenesis, in situ hybridization was used to localize messenger RNA (mRNA) transcripts of cathepsin L, D, and S in the epithelium at different stages of the spermatogenic cycle in the rat. Cathepsin L mRNA was found to localize almost exclusively near the basal lamina of the epithelium. At stages VI and VII of the cycle before spermiation, the signal of cathepsin L mRNA was so intense that it formed a complete dark precipitate near the basal lamina encircling the entire tubule. At stage VIII, the expression of cathepsin L was completely abolished, and no staining of cathepsin L mRNA was seen in the epithelium. The mRNA of cathepsin D and S was found near the basal lamina, a finding consistent with their localization in Sertoli cells and possibly primary spermatocytes in almost all stages, but peaked at stages VII-IX and VII-VIII of the cycle, respectively, at the time before and during spermiation. These results illustrate the possible involvement of these proteases in facilitating germ cell movement and spermiation. To examine whether germ cells express any of these cathepsin genes, spermatocytes with a purity of greater than 95% were isolated from 15-day-old rat testes by Percoll gradient centrifugation for reverse transcriptase-polymerase chain reaction. It was found that primary spermatocytes expressed multiple cathepsin genes, including cathepsin B, C, D, H, L, and S. Furthermore, the expression of cathepsin L by germ cells isolated from 15-day-old rats (largely spermatocytes and spermatogonia) can be stimulated by Sertoli cell-enriched culture medium in a dose-dependent manner, but not by germ cell-conditioned medium. These results reveal that germ cell function can be regulated by Sertoli cells. Moreover, these results suggest that germ cells may play an active role in the overall testicular protease expression. Also, we present evidence suggesting there is cross-talk between Sertoli and germ cells, since the expression of cathepsin L in each cell type is regulated by one another via either soluble factors or cell-cell contact.
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PMID:Evidence for cross-talk between Sertoli and germ cells using selected cathepsins as markers. 987 20

The aim of this work was to study which genes upregulated by the IFN-gamma/STAT1 system in human muscle might be involved in the process of muscle fiber atrophy in dermatomyositis (DM). These proteins included proteases (cathepsins B and L, calpain), proteins implicated in apoptosis and cell cycle (Bcl-x(l), Fas, p21), structural proteins (beta-actin, utrophin, desmin), and other proteins whose expression is known to be modified by IFN-gamma (neural cell adhesion molecule (N-CAM), major histocompatibility complex-I (MHC-I)). We performed immunocytochemistry, Western blot, and semiquantitative reverse transcriptase-polymerase chain reaction using human muscle cultures. We found upregulation of cathepsins B and L, bcl-x(l) and p21 while N-CAM, calpain, utrophin, desmin, beta-actin and Fas remained at basal levels. Immunohistochemistry on frozen sections from biopsies of patients with different muscle diseases showed upregulation of cathepsin L and calpain in perifascicular muscle fibers in DM. In view of these results, the increased expression of cathepsins L and B after IFN-gamma stimulation in muscle cultures and its inhibition using fludarabine, a STAT1 blocker, further support our previous studies and suggest that the increased expression of cathepsins detected in perifascicular muscle fibers in DM is mediated by IFN-gamma/STAT1 and contributes to their atrophy.
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PMID:Cathepsins are upregulated by IFN-gamma/STAT1 in human muscle culture: a possible active factor in dermatomyositis. 1155 41

An amphioxus complementary DNA, AmphiCL, encoding cathepsin L proteinase was isolated from the gut cDNA library of Branchiostoma belcheri tsingtauense. It is 1480 bp long, and its longest open reading frame codes for a precursor protein, which consists of 327 amino acid residues including a signal peptide (preregion), a propeptide, and a mature proteinase. Northern blot showed that AmphiCL was expressed in the gill, testis, hepatic cecum, and hind-gut with a molecular size of about 1480 bp. AmphiCL was also expressed at low level in the muscle, notochord, and ovary as revealed by the more sensitive reverse transcriptase polymerase chain reaction techniques. Semiquantitative RT-PCR also showed that although AmphiCL expression in the gut was significantly downregulated by feeding Arthrospira platensis powder, a protein-rich food, its expression in the same tissue was upregulated by exposure to lipopolysaccharide, an integral component of the outer membrane of gram-negative bacteria. This suggests that although the involvement of AmphiCL in food digestion remains to be confirmed, AmphiCL may play a role in inflammatory reaction in amphioxus.
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PMID:Characterization and expression of AmphiCL encoding cathepsin l proteinase from amphioxus Branchiostoma belcheri tsingtauense. 1577 12

Platelet-derived growth factor (PDGF)-BB and PDGF-DD mediate mesangial cell proliferation in vitro and in vivo. While PDGF-BB is a ligand for the PDGF alpha- and beta-receptor chains, PDGF-DD binds more selectively to the beta-chain, suggesting potential differences in the biological activities. Signal transduction and regulation of gene expression induced by PDGF-BB and -DD were compared in primary human mesangial cells (HMCs), which expressed PDGF alpha- and beta-receptor subunits. The growth factor concentrations used were chosen based on their equipotency in inducing HMCs proliferation and binding to the betabeta-receptor. Both growth factors, albeit at different concentrations induced phosphorylation and activation of extracellular signal-regulated kinase 1 (ERK1) and ERK2. In addition, PDGFs led to the phosphorylation and activation of signal transducers and activators of transcription 1 (STAT1) and STAT3. HMCs proliferation induced by either PDGF-BB or -DD could be blocked by signal transduction inhibitors of the mitogen-activated protein kinase-, Janus kinase (JAK)/STAT-, or phosphatidyl-inositol 3-kinase pathways. Using a gene chip array and subsequent verification by real-time reverse transcriptase (RT)-polymerase chain reaction, we found that in HMC genes for matrix metalloproteinase 13 (MMP-13) and MMP-14 and, to a low extent, cytochrome B5 and cathepsin L were exclusively regulated by PDGF-BB, whereas no exclusive gene regulation was detected by PDGF-DD. However, at the protein level, both MMP-13 and -14 were equally induced by PDGF-BB and -DD. PDGF-BB and -DD effect similar biological responses in HMCs albeit at different potencies. Rare apparently differential gene regulation did not result in different protein expression, suggesting that in HMCs both PDGFs exert their biological activity almost exclusively via the PDGF beta-receptor.
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PMID:Biological responses to PDGF-BB versus PDGF-DD in human mesangial cells. 1655 24

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