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)

The cellular lineage of sinonasal T/NK (natural killer) cell lymphoma remains controversial. Lineage assignment is difficult because T cells and NK cells have a similar morphology and surface markers. Consequently, the assignment must depend heavily on the status of T-cell receptor (TCR) rearrangement. A monoclonal TCR rearrangement supports a T lineage; however, a corresponding monoclonality test for NK cells has not yet been established. Each NK cell bears a distinct set of killer cell immunoglobulin (Ig)-like receptors (KIRs) that are randomly distributed over three groups. In principle, restriction of the KIR repertoire signifies a monoclonal or possibly oligoclonal NK-cell proliferation, just as Ig light-chain restriction usually indicates a monoclonal B-cell neoplasm. Using a novel group-specific reverse transcriptase-polymerase chain reaction, we found a restricted KIR repertoire in most sinonasal lymphomas (9 of 10), but only rarely in T-cell lymphomas (2 of 10) or reactive conditions involving T/NK cells (1 of 10). KIR+ sinonasal lymphomas usually lacked a monoclonal TCR-gamma rearrangement pattern, expressed another NK cell receptor, NKG2a, and were usually CD56-positve, cyclin-dependent kinase-6 (CDK6)-positive, CD44-negative, a phenotype already reported to indicate a true NK cell lineage. We conclude that, although sinonasal lymphomas have heterogeneous genotypes and phenotypes, a restricted KIR repertoire without TCR-gamma rearrangement provides preliminary support for the monoclonality hypothesis and can be used for defining a true NK-cell lineage in a subset of sinonasal lymphomas.
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PMID:Restricted killer cell immunoglobulin-like receptor repertoire without T-cell receptor gamma rearrangement supports a true natural killer-cell lineage in a subset of sinonasal lymphomas. 1169 28

We analyzed the immunohistochemical expression of the metastasis-associated protein, CD44v3, in 46 primary human malignant melanomas (MMs). This is the first time that the v3 splice variant of CD44 was found to be expressed in human melanomas (15 of 46), ranging from 3% to 35% of the cell population in the positive tumors. The expression of CD44v3 was observed in tumors thicker than 1.0 mm, and one-third of these tumors proved to be positive irrespective of the thickness. Patients were followed for a minimum of 61 months. The onset of lymph node or organ metastases occurred not later than 58 months and 60 months, respectively. Of the 15 CD44v3 positive tumors, 14 were observed in the organ metastatic tumor group, comprising the majority of those cases (14 of 21), and this association proved to be statistically significant compared with the non-metastatic (P<0.05) and lymph-node metastatic cases (P<0.01). CD44v3 expression in melanoma was also confirmed at the protein and messenger (mRNA) level in several human melanoma cell lines using flow cytometry and reverse transcriptase polymerase chain reaction analysis. In parallel to CD44v3, MMP-2 expression (determined using immunohistochemistry) was significantly elevated (P<0.05) but only in the organ metastatic group of MM. The 5-year survival of patients having thicker tumors than 1.0 mm (where v3 expression occurred) who had CD44v3+ tumors was significantly lower than those of the negative ones (35.7% versus 68.2%, respectively; P=0.025). Finally, we observed that the CD44v3-expressing tumors were characterized by significantly higher MMP-2 expression than the CD44v3-negative tumors (P<0.001), indicating a possible correlation between CD44v3- and MMP-2-positive phenotype and the organ metastatic potential of MM.
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PMID:Expression of CD44v3 splice variant is associated with the visceral metastatic phenotype of human melanoma. 1176 82

CD44 is a family of transmembrane glycoproteins that has been linked to carcinogenesis and metastasis. It serves as a major receptor for hyaluronate. The v3 isoform binds to growth factors through heparan sulfate side chains and targets these factors to their high-affinity signal transducing receptors. The purpose of this study was to analyze the expression of CD44 v3 and v4 in human colorectal carcinoma with real-time reverse transcriptase-polymerase chain reaction (RT-PCR). Our results show that 19 of 56 cases (33.9%) showed a greater than 2-fold increase in CD44 v3 expression in tumors as compared with matched normal mucosa, while 15 of 44 cases (34.1%) showed a greater than 2-fold increase in CD44 v4 expression. There was a marked variation in fold-differences of CD44 gene expression between tumor and normal samples (T/N ratios) among the tumors. This prompted us to correlate the T/N ratios of the tumors with clinicopathologic characteristics. Interestingly, overexpression of CD44 v3 mRNA was associated with the presence of vascular invasion (P <.05). Similarly, overexpression of CD44 v4 was significantly correlated to increased depth of invasion (P <.05). Results from the present study suggest that overexpression of CD44 v3 and v4 mRNA levels may be useful clinical markers for colorectal carcinoma invasiveness.
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PMID:Expression of CD44 variants in colorectal carcinoma quantified by real-time reverse transcriptase-polymerase chain reaction. 1187 46

The analysis of RNA splicing is important to understanding the diversity in protein sequences at specific disease loci, in the immune response, and across the proteome. The presence of each exon in a mature mRNA formed from a genomic sequence of n exons can be represented by a Boolean variable, enabling mRNA structure to be encoded by an n-bit binary number. The CD44 locus has been studied as an example of a variantly spliced RNA. Microarray methods can be used to address RNA splicing provided they exhibit high fidelity. Our previous work showed that the arrayed primer extension (APEX; single-nucleotide polymerase extension of microarrays of DNA primers) method gives high-fidelity, digital detection of nucleic acid sequences, and it has been used for the solution of Boolean computing problems. APEX was adapted to RNA analysis by the use of reverse transcriptase and arrays of primers specific to each exon in the CD44 locus. "Splicotypes" were readily assigned for a number of variant RNA templates. Because CD44 is known to be aberrantly spliced in a number of cancers, the RNA APEX method with a CD44 microarray was applied to samples from primary tumors of individual patients. Up to four different splicing forms of CD44 were detected, whereas there have been no previous reports of the presence of more than two CD44 isoforms within the same tissue.
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PMID:Arrayed primer extension computing with variant mRNA splice forms. Multiple isoforms of CD44 in a human breast tumor. 1198 38

CA IX is a tumour-associated carbonic anhydrase with proposed roles in pH modulation and intercellular communication. Its distribution was examined in normal, benign and malignant breast tissues and compared with expression of breast tumour markers including oestrogen receptor, c-erbB2, c-erbB3 and CD44. Tissue specimens were analysed using immunohistochemistry and/or reverse transcriptase-polymerase chain reaction (RT-PCR). CA IX was detected by IHC in 12/26 (46%) malignant tissues, 4/36 (11%) benign lesions, but not in 10 normal breasts. Staining was mostly confined to plasma membranes of abnormal epithelial cells, but in five cases was found in adjacent stroma. Semi-quantitative RT-PCR detected CA9 mRNA in 25/39 (64%) malignant tumours, 11/33 (33%) benign lesions, but in none of three normal breasts. Comparative RT-PCR analysis of malignant tissues revealed a relationship between CA9 positivity and c-erbB2 overexpression (p=0.05). Moreover, CA9-positive specimens displayed a significantly higher median level of c-erbB2 than CA9-negative ones (p=0.02). No significant association was found with the other markers. The results of this study support the possible importance of CA IX for breast carcinogenesis and suggest its potential use as a breast tumour marker.
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PMID:Expression of carbonic anhydrase IX in breast is associated with malignant tissues and is related to overexpression of c-erbB2. 1211 77

Although low-grade cartilage neoplasms typically consist of hyaline-like cartilage, most of them also contain some fibrocartilaginous regions. CD44, a cell surface receptor for hyaluronan, has been identified in cartilage. A family of alternatively spliced mRNA containing the variant 6 (v6) exon sequence of CD44 has been linked to several types of neoplasms. We hypothesized that expressions of v6-containing CD44 species are associated with fibrocartilaginous regions of low-grade cartilage neoplasms. To test this hypothesis we performed reverse transcriptase-polymerase chain reaction (RT-PCR) and immunohistochemical analysis on eight samples: four from normal articular cartilage, one from a synovial chondromatosis, and three chondrosarcomas which were graded as I and I/II. The standard CD44s and a unique v6-containing CD44 species (CD44v6-10) were identified in all tissue samples by RT-PCR analysis. Immunohistochemically, using an antibody that cross-reacted with all CD44 species, CD44 was localized to the cell surface, lacuna wall and intracellular compartment of the chondrocytes in the middle and deep zone of normal cartilage, as well as with cells throughout the neoplastic masses. Utilizing an antibody specific for v6-containing CD44 species, the variant species was identified throughout cells of the middle and deep zone of normal cartilage, and localized selectively to intracellular positions. In neoplastic masses, v6-containing CD44 species were found associated only with cells in the hyaline-like cartilage, but not in the fibrocartilaginous regions. Thus a differential expression of the v6-containing CD44 species in the neoplastic masses containing both hyaline-like cartilage and fibrocartilaginous regions was observed when compared to its homogenous expression in normal hyaline cartilage. An involvement between the lack of the variant CD44 (v6-containing) and altered tissue phenotype (e.g., fibrocartilaginous) is suggested.
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PMID:Expression of CD44 in human neoplastic and normal hyaline cartilage. 1218 Jun 11

To elucidate the effects of interleukin-1beta (IL-1beta) on osteogenic protein-1 (OP-1) gene expression in a polylayer culture of rabbit articular chondrocytes, we measured rabbit OP-1 mRNA using quantitative TaqMan reverse transcriptase-polymerase chain reaction (RT-PCR) techniques. Rabbit articular chondrocytes were isolated and cultured in minimum essential medium eagle alpha modification containing 10% fetal bovine serum for 7 days. IL-1beta was then added and cultures were continued for 48 or 96 hours. OP-1 gene expression was detected in cell cultures both with and without addition of IL-1beta. However, the level of expression was very low in the control group. OP-1 gene expression was significantly increased about 450- to 800-fold in IL-1beta-treated groups (0.1, 1, and 10 ng/ml) versus the control group. Evaluation of serial changes in OP-1 expression after addition of IL-1beta (10 ng/ml) revealed that OP-1 gene expression increased rapidly after addition of IL-1beta, reaching a peak at 48 hours, and then decreasing. Simultaneous assay of CD44 expression demonstrated a rapid increase, similar to that of OP-1 expression, following addition of IL-1beta: this was followed by a more gradual increase. Assay of hyaluronan synthase-2 (HAS-2) expression following addition of IL-1beta showed an increase after OP-1 expression had already reached a peak. Our results demonstrate that OP-1 expression is induced by IL-1beta and suggest that this expression, like that of HAS-2, may play a role as a protective mechanism against inflammatory cytokines.
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PMID:Induction of osteogenic protein-1 expression by interleukin-1beta in cultured rabbit articular chondrocytes. 1223 82

In response to the gonadotropin surge, the compact cumulus-oocyte complex (COC) undergoes expansion by synthesis of the mucopolysaccharide hyaluronan (HA) accompanying oocyte maturation. The objective of the present study was to quantify mRNA transcripts of the HA synthase (HAS) 1, HAS2, and HAS3 and the HA-receptors CD44 and RHAMM (receptor for HA-mediated motility). Additionally, we determined the histological localization of HA and its receptor, CD44, in maturing bovine COCs and cultured granulosa cells (GCs). Full-length transcript of bovine HAS2 and a part of the bovine RHAMM sequence has been made available. Real-time reverse transcriptase-polymerase chain reaction was used for individual mRNA expressions of bovine COCs in comparison to follicular GC gonadotropin treatment. Localization of CD44 and HA were done by immunohistochemistry and biotinylated HA-binding protein, respectively. Gonadotropins caused a rapid, 120-fold increase of HAS2 mRNA, whereas a delayed, 2-fold up-regulation of HAS3 mRNA was observed. The HAS1 transcripts were barely detected. Expression of CD44 mRNA greatly increased during in vitro maturation of COCs, indicating an important role when compared to an unchanged, steady-state RHAMM expression. As a consequence, HA was locally enriched after COC expansion, but only limited change was observed in the GCs. In cultured GCs, HAS2 expression was stimulated through FSH application, followed by the effective treatments of FSH+LH and LH. Treatment with LH induced the highest increase of the CD44 receptor, followed by FSH and FSH+LH treatments. These results suggest that HAS2 is mainly responsible for rapid HA synthesis in bovine COCs and GCs. In bovine COCs, the transcriptional up-regulation of both HAS2 and the receptor CD44 appear to be important prerequisites for initiating HA-mediated effects during final oocyte development and sperm-egg interaction.
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PMID:Expression of hyaluronan synthases and corresponding hyaluronan receptors is differentially regulated during oocyte maturation in cattle. 1262 Sep 32

The gastrointestinal epithelium is known to undergo constant and rapid renewal resulting in millions of cells being shed into the fecal stream every day. The conventional wisdom was that these cells disintegrate upon exfoliation and will not survive the transit through the intestinal tract. In 1990, we (P.N.) made the discovery that a significant number of these cells remain intact and viable and that they can be isolated. The implications of this important discovery became apparent when we demonstrated that these cells are exclusively of colonic origin, are anatomically representative of the entire colon, and can be used for clinical investigations of disease processes. The term coprocytobiology (CCB) was coined to encompass the broad range of applications of this new technology. The somatic cell sampling and recovery (SCSR) process involves the isolation of exfoliated colonocytes from a small sample of stool ( approximately 1 g) collected and transported in a unique medium at ambient temperature, providing cells for the detection of a number of biomarkers of disease propensity. These exfoliated colonocytes express cytokeratins indicating epithelial lineage as well as colon-specific antigen. Over the years, the study of exfoliated colonocytes has provided striking new insights into the biology of colon cancer and inflammatory bowel disease, including detection of p53 gene mutations, reverse transcriptase polymerase chain reaction amplification, and identification of CD44 splice variants, neoplasia-associated specific binding of plant lectins, and expression of COX-2, the inducible form of cyclooxygenase. The functional diversity of cells isolated by SCSR is revealed by the demonstration of cell surface markers such as secretory component, IgA, and IgG on the one hand and the amplification and cloning of the human insulin receptor and the expression of the multidrug resistance gene mdr-1 on the other hand. This review portrays the immense potential of CCB as a powerful tool for investigating the pathophysiology of disease, identifying genetic variants in pharmacogenetics, assessment of mucosal immunity, and several other applications that use somatic cells.
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PMID:Coprocytobiology: on the nature of cellular elements from stools in the pathophysiology of colonic disease. 1270 72

Tissue anoxia occurs early in wound healing. This is accompanied by production of lactate followed by increased hyaluronan and CD44 expression, suggesting a cause and effect relationship. Fibroblasts increased hyaluronan and CD44 when lactate was added to cultures. Increased deposition of hyaluronan correlates with greater turnover. In current models of hyaluronan catabolism, it is tethered to cell surfaces by CD44 in caveolin-enriched invaginations. It is cleaved to 20-kDa fragments by Hyal-2 on the plasma membrane, endocytosed, and delivered ultimately to lysosomes, and further digested by Hyal-1. Sequence analyses of promoter regions of genes for CD44, caveolin-1, Hyal-1, and -2 revealed multiple AP-1 and ets-1 response elements. To test their relevance, RNA from lactate-treated fibroblasts was analyzed by reverse transcriptase-polymerase chain reaction. Increased transcripts of c-fos, c-jun, c-ets, Hyal-1, -2, CD44, and caveolin-1 mRNAs were observed. We have thus identified lactate-activated genes important in the wound healing responses. Similar responses facilitating tumor progression, the Warburg effect, may share such mechanisms.
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PMID:Lactate-sensitive response elements in genes involved in hyaluronan catabolism. 1273 17


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