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 molecular mechanisms regulating the biogenesis of the first desmosomes to form during mouse embryogenesis have been studied. A sensitive modification of a reverse transcriptase-cDNA amplification procedure has been used to detect transcripts of the desmosomal adhesive cadherin, desmocollin. Sequencing of cDNA amplification products confirmed that two splice variants, a and b, of the DSC2 gene are transcribed coordinately. Transcripts were identified in unfertilized eggs and cumulus cells and in cleavage stages up to the early 8-cell stage, were never detected in compact 8-cell embryos, but were evident again either from the 16-cell morula or very early blastocyst (approx 32-cells) stages onwards. These two phases of transcript detection indicate DSC2 is encoded by maternal and embryonic genomes. Previously, we have shown that desmocollin protein synthesis is undetectable in eggs and cleavage stages but initiates at the early blastocyst stage when desmocollin localises at, and appears to regulate assembly of, nascent desmosomes that form in the trophectoderm but not in the inner cell mass (Fleming, T. P., Garrod, D. R. and Elsmore, A. J. (1991), Development 112, 527-539). Maternal DSC2 mRNA is therefore not translated and presumably is inherited by blastomeres before complete degradation. Our results suggest, however, that initiation of embryonic DSC2 transcription regulates desmocollin protein expression and thereby desmosome formation. Moreover, data from blastocyst single cell analyses suggest that embryonic DSC2 transcription is specific to the trophectoderm lineage. Inhibition of E-cadherin-mediated cell-cell adhesion did not influence the timing of DSC2 embryonic transcription and protein expression. However, isolation and culture of inner cell masses induced an increase in the amount of DSC2 mRNA and protein detected. Taken together, these results suggest that the presence of a contact-free cell surface activates DSC2 transcription in the mouse early embryo.
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PMID:Regulation of desmocollin transcription in mouse preimplantation embryos. 753 56

A third human desmocollin, designated DSC3, was identified in foreskin epidermis by reverse transcriptase-polymerase chain reaction (PCR) using degenerate desmocollin primers. cDNA clones covering the entire coding sequence of the longer DSC3 splice variant were isolated and sequenced. Sequence comparisons indicated that this new desmocollin showed greater homology (67% amino acid identity) with the original human desmocollin (now designated DSC2) than with DSC1 (52% amino acid identity) although it had a unique potential cell adhesion recognition site (YAS). DSC3 was assigned to chromosome 18 by PCR analysis of rodent-human somatic cell hybrids, where it appears to be closely linked to all the other desmosomal cadherin genes. The expression of the three human desmocollins was examined in foreskin epidermis by in situ hybridization with 3'-untranslated riboprobes and by immunofluorescence with isoform-specific anti-peptide antibodies. DSC1 was present in the upper spinous/granular layers but not in the basal/lower spinous layers of the tissue. DSC2 and DSC3 were present in most of the living layers of the epidermis. DSC1 was not detected in any of the nonkeratinizing human epithelia examined (buccal mucosa, cervix, esophagus), indicating that it is specific for the keratinizing epithelium of the epidermis. However, all these internal epithelia expressed DSC2 and DSC3, and both were present in most of the living layers of the tissues including the basal layers.
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PMID:The desmocollins of human foreskin epidermis: identification and chromosomal assignment of a third gene and expression patterns of the three isoforms. 766 6

The cadherins are a family of calcium-binding membrane glycoproteins. Most cadherins are capable of acting as cell adhesion molecules (CAMs). In order to begin a thorough analysis of the roles of these CAMs in the testis, we employed a reverse transcriptase-polymerase chain reaction (RT-PCR) strategy to identify the cadherins expressed in this tissue at various stages of development. Oligonucleotides encoding amino acid sequences that are conserved among all of the known cadherins were used as primers in the RT-PCR, with cDNA preparations of fetal, newborn, 7-day, 21-day, and adult mouse testes employed as templates. The PCR products were subcloned into a plasmid vector and sequenced. On the basis of the nucleotide sequences of these PCR products, we have determined that five previously characterized cadherins (E-cadherin, N-cadherin, P-cadherin, K-cadherin, and OB-cadherin), as well as two novel cadherins (T1-cadherin and T2-cadherin), are expressed at various stages during testicular development. In order to determine the expression patterns of these cadherins, we ascertained the mRNA levels of each cadherin normalized to the levels of hypoxanthine phosphoribosyltransferase mRNA in fetal, newborn, 7-day, 21-day, and adult mouse testes. We observed that N-cadherin mRNA is expressed at all stages of testicular development, with maximal levels being present in the testes of 21-day-old mice. Furthermore, we found that E-, P-, K-, OB-, and T2-cadherin mRNAs are all expressed in the fetal gonad. The testicular levels of these cadherin mRNAs decreased dramatically after birth. Conversely, T1-cadherin mRNA was not detected in the fetal, newborn, and 7-day-old testes but was present in 21-day-old and adult testes. T1-cadherin levels were 10-fold higher in the testes of adult mice, compared to the levels found in the testes of 21-day-old mice. We speculate that these cadherins will be found to be intimately involved in mediating cell interactions during testicular development.
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PMID:A comprehensive survey of the cadherins expressed in the testes of fetal, immature, and adult mice utilizing the polymerase chain reaction. 887 95

Cadherin molecules are essential for tissue morphogenesis and are also related to cancer invasion and metastasis. Although normal melanocytes express E- and P-cadherin, the activity and expression of E- and P-cadherin in melanoma cells are still unknown. We measured the homophilic adhesion activity of human normal epidermal melanocytes and the melanoma cell lines MeWo and A375. The melanoma cells showed stronger homophilic adhesion activity than did the melanocytes, despite the lower expression of E- and P-cadherin in the melanoma cells. This result suggested that melanoma cells expressed other types of homophilic adhesion molecules. Using degenerate primers to amplify multiple cadherin subtypes, we performed a polymerase chain reaction (PCR) with the first strand of cDNAs generated by reverse transcription of the mRNAs of the melanoma cells, and we isolated two known cadherin fragments, N-cadherin and PC42, and six novel cadherin fragments, cadherins ME1-ME6. The reverse transcriptase-PCR using specific primers of cadherins including E-, P-, and N-cadherins, PC42, and cadherins ME1-ME6 revealed that the melanoma cells expressed more kinds of cadherin molecules than did the melanocytes. Such cadherins may play an important role in melanoma cell-cell adhesion.
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PMID:Identification of novel cadherins expressed in human melanoma cells. 918 20

Two isoforms of the human cadherin-11/OB-cadherin gene, the intact and the variant forms, had been isolated from an osteosarcoma cDNA library. The intact form has a typical cadherin structure, whereas the variant form, generated by alternative splicing, encodes a cytoplasmic domain that is completely different from that of the intact form and lacks a homophilic cell-cell adhesion ability. At the protein level, the secreted form generated from the intact cadherin-11 is present. We examined the expression of the intact and the variant forms of cadherin-11 in 23 primary and metastatic osteosarcomas from 22 patients by reverse transcriptase-polymerase chain reaction (RT-PCR) analyses, revealing that all 23 tumors in the patients expressed the variant form and three of them expressed it prominently. On the other hand, Western blot analyses of six tumors showed that the secreted form was strongly expressed, and furthermore, expression of N-cadherin was extremely low. Overexpression of the intact cadherin-11 cDNA in osteosarcoma cell lines demonstrated that the secreted form is derived from the intact form of cadherin-11 in osteosarcoma. Immunohistochemically, cadherin-11, N-cadherin, and beta-catenin were expressed at the cell surface of fetal osteoblasts, whereas in osteosarcoma cells, they were expressed only focally or weakly in the cytoplasm. Considering the function of cadherin in carcinomas, it is suggested that the anomalous expression of human cadherin-11 in osteosarcoma and the reduced expression of N-cadherin play a role in metastasis and the irregular morphology in the highly malignant mesenchymal tumor.
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PMID:Anomalous cadherin expression in osteosarcoma. Possible relationships to metastasis and morphogenesis. 1055 Mar 12

T-cadherin is a unique member of the cadherin superfamily that shares the ectodomain organization with classical cadherins, but lacks both transmembrane and cytoplasmic regions and is instead anchored to the plasma membrane through a glycosyl-phosphatidylinositol (GPI) moiety. The function of T-cadherin has not been revealed yet. The special structure of T-cadherin might endow this molecule with specific intracellular targeting properties and functions that are distinct from classical cadherins. T-cadherin was originally cloned from chicken embryo brain and then was also found in mouse and human nervous and cardiovascular systems; however, T-cadherin in the keratinocytes and skin tissue is still an unknown area that remains to be explored. To test whether the unusual truncated T-cadherin is expressed in keratinocytes, we performed the reverse transcriptase-polymerase chain reaction of T-cadherin, as well as several classical cadherins (E-, P-, and N-cadherin), on the mouse keratinocyte cell line Pam212, fibroblast NIH3T3, and melanoma cell B16. The result indicated that mouse keratinocytes expressed the mRNA of truncated T-cadherin apart from classical cadherins, E-, and P-cadherin. To confirm the expression of T-cadherin in mouse keratinocytes, immunocytochemistry staining was carried out on Pam212 cells by using rabbit anti-T-cadherin antibody and rat antimouse E- and P-cadherin antibody. The result of immunofluorescence staining proved that T-cadherin was expressed in mouse keratinocytes. In order to analyze the distribution patterns of T-cadherin and classical cadherins on the keratinocytes, 3D scanning was performed by using a confocal microscope. From the Z-sections and XZ-sections, it was clearly demonstrated that T-cadherin was distributed diffusely on the whole cell surface, while E- and P-cadherin were concentrated on the cell-cell contacts. To examine the expression and the localization of T-cadherin on skin tissue, the frozen sections of the mouse back skin were immunohistochemically labeled by using anti-T-cadherin antibody. It was found that T-cadherin was intensively expressed only on the basal cell layer of the mouse skin. Apart from mouse keratinocytes and mouse skin, we further examined the expression of T-cadherin in human keratinocytes and human skin by western blot, immunocytochemistry, and immunohistochemistry staining. The same results were achieved with human samples. In this study, we found and verified that T-cadherin was expressed on the mouse and human keratinocytes and specifically localized on the basal cell layer of skin. The nature of T-cadherin function and its mechanism of localization at the basal cell layer of skin are important issues to be addressed concerning this unique member of the cadherin family and its physiologic and pathologic roles in the skin.
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PMID:Expression of T-cadherin in Basal keratinocytes of skin. 1206 Apr 6

Members of the cadherin superfamily mediate critical interactions in tissue differentiation and organogenesis, including differentiation and maintenance of the intestine. In this study, we report the identification and expression of a novel cadherin in the intestinal epithelium. We identified this cDNA by subtraction hybridization and obtained subsequent clones by screening a human cDNA library. Tissue distribution of the mRNA encoding the cadherin was assessed by RNA blot, reverse transcriptase PCR, and in situ hybridization. Protein expression was analyzed by protein blot and immunohistochemistry. The cDNA encodes an integral membrane protein with four consecutive cadherin binding domains followed by a series of mucin domains, a unique feature of this cadherin. Differences in the mucin domains account for four splice-forms. Multiple potential SH3-binding domains and a single potential PDZ-binding domain follow the transmembrane domain. Analysis revealed expression in the liver, kidney, and intestine. Three splice variants were found in the embryonic intestine as early as embryonic d 13 and in the adult intestine. The mRNA localizes to the mature enterocytes throughout the mouse small intestine and the protein, including several species from 90 to 100 kD, resides on the enterocyte basolateral membrane. We have identified intestinal expression of a novel cell cadherin with features suggesting the potential to transduce signals from neighboring cells to the cytoplasm.
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PMID:Expression of a novel cadherin in the mouse and human intestine. 1502 44

Tumor cell invasion and metastasis are the hallmark of malignant neoplasm. Despite advances in the management of thyroid carcinoma and other solid tumors, metastasis continues to be the most significant cause in cancer mortality. To gain new insights into this complex process in thyroid carcinoma, we established a thyroid carcinoma cell line (ARO-met2) with high metastatic capacity to the lung by sequential passage of a human anaplastic thyroid cancer cell line (ARO) through the lung of a nude mouse. Global patterns of gene expression were analyzed in cells of the parental ARO and the ARO-met2, using Atlas human cancer 1.2 array with 1176 cancer-related genes. In total, 184 genes were differentially expressed more than 1.5 times, and 64 genes were differentially expressed over two times. Among those 64 genes, 43 were overexpressed, and 21 genes were underexpressed. Many genes whose increased expression was thought to be related to tumor progression were identified, such as c-Met, ezrin, integrin, motility-related protein-1, cadherin, and S100A4. The most highly expressed gene is the S100A4 (8-fold higher than control), which is a member of a small calcium binding protein family and is involved in the cell proliferation and cancer progression. The S100A4 overexpression in the ARO-met2 cells was later confirmed by Northern blot and real-time reverse transcriptase-PCR. Analysis of 49 thyroid tumor specimens by real-time reverse transcriptase-PCR (eight benign goiters, 36 papillary, and five anaplastic carcinomas) revealed that S100A4 overexpression was present in most advanced thyroid carcinomas and lymph node metastases, and was associated with poor prognosis. None of the benign goiters was found to have S100A4 overexpression. These data suggest that S100A4 could be used as a prognostic marker for thyroid carcinoma. Given that S100A4 is involved in tumor progression and metastasis, it may be a potential target for therapeutic intervention.
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PMID:Microarray analysis of metastasis-associated gene expression profiling in a murine model of thyroid carcinoma pulmonary metastasis: identification of S100A4 (Mts1) gene overexpression as a poor prognostic marker for thyroid carcinoma. 1557 71

Cadherins are a large family of cell-cell adhesion molecules acting in a homotypic, homophilic manner that play an important role in the maintenance of tissue integrity. In the human kidney, several members of the cadherin family (including E- and N-cadherin, cadherin-6, -8 and -11) are expressed in a controlled spatiotemporal pattern. Cadherin-16, also called kidney-specific (Ksp-) cadherin, is exclusively expressed in epithelial cells of the adult kidney. In renal cell carcinomas (RCCs), which are considered to originate from epithelial kidney tubular cells, a complex pattern of cadherin expression can be observed, but Ksp-cadherin expression has not been analysed so far. In the present study, we show that the expression of Ksp-cadherin is completely abrogated in RCCs. Whereas Ksp-cadherin can be detected at later stages of tubulogenesis during human renal development and in the distal tubules of adult kidneys, no expression was found by immunohistochemistry or Western blot analysis in RCC tumour tissues and several RCC cell lines. However, despite the lack of protein expression, mRNA synthesis of Ksp-cadherin could be detected by reverse transcriptase-polymerase chain reaction analysis in all RCC tissues and most of the RCC cell lines studied, although at a reduced level. The loss of Ksp-cadherin protein was only observed in the malignant part of the tumour kidneys, whereas in the normal part of the affected kidneys Ksp-cadherin expression was clearly detected. These results indicate a downregulation of Ksp-cadherin in RCC and suggest a role for this cell adhesion molecule in tumour suppression.
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PMID:Expression of Ksp-cadherin during kidney development and in renal cell carcinoma. 1588 5

Because susceptibility or resistance of Biomphalaria glabrata to the trematode Echinostoma caproni correlates with differential hemocytic adhesive properties, we compared the expression of genes involved in adhesion processes between hemocytes from susceptible and resistant snails. Quantitative reverse transcriptase-PCR analysis revealed four genes whose transcripts were differentially represented between hemocytes from resistant and susceptible snails. These genes encode two dermatopontin-like, one matrilin-like and one cadherin-like proteins. Expression analyses performed following parasite exposure suggested that dermatopontins may be involved in the compatibility differences between these strains. We also investigated expression levels on whole snails of different genes potentially involved in extracellular matrix structure or coagulation. Our results support the hypothesis that susceptible snails possess a hemolymph coagulation-like system that is more potent than that of resistant snails. This system may prevent hemocyte migration towards the parasite larvae and therefore facilitate parasite settlement in susceptible snails.
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PMID:Compatibility in the Biomphalaria glabrata/Echinostoma caproni model: potential involvement of adhesion genes. 1631 Jul 90


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