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)

Besides their regulatory role in embryogenesis, homeobox (HOX) genes are expressed in a specific manner in hematopoietic cell lineages, implying a role in the molecular regulation of hematopoiesis. Some HOX C cluster genes are found to be expressed in lymphoid cells of mice and humans. Their function and expression in normal hematopoiesis are still largely unknown. We have studied the mRNA expression of HOXC4, HOXC5, and HOXC6 in several stages of lymphocyte maturation by reverse transcriptase-polymerase chain reaction (RT-PCR) and RNA in situ hybridization (RISH). We examined CD34+/CD38low and CD34+/CD38high cells obtained from normal donor bone marrow (BM), a panel of 19 lymphoid cell lines, several types of leukemias and non-Hodgkin's lymphomas (NHL), and lymphocytes isolated from tonsillar tissue and peripheral blood (PB). HOXC4 and HOXC6 were found to be expressed during maturation in B- and T-lymphoid cells. The expression of each gene was found to be initiated at different cell maturation stages. HOXC4 transcripts were present in CD34+/CD38low cells, which are thought to comprise stem cells and noncommitted progenitor cells, and in subsequent stages to terminally maturated lymphoid cells. HOXC6 expression is initiated in equivalents of prothymocyte and pre-pre-B cell stage and remains present in mature cells. However, HOXC5 is only expressed in neoplastic cell lines and in neoplastic cells of NHL, but not in CD34+ BM cells, nor in resting or activated lymphoid cells isolated from tonsil, PB, or in leukemia cells. In cell lines, weak expression of HOXC5 is initiated in equivalents of pre-B cell and common thymocyte stage and is continuously expressed in mature cell lines. Semi-quantitative RT-PCR showed that expression levels of HOXC5 were much lower than those of HOXC4 and HOXC6; furthermore an increase of expression of HOXC4, HOXC5, and HOXC6 during lymphoid cell differentiation was demonstrated. Thus, mainly mature lymphoid cell lines and neoplastic cells of NHL do express HOXC5, in contrast to the lack of expression in normal lymphoid cells and leukemias. These findings suggest involvement of HOXC5 in lymphomagenesis.
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PMID:Expression of HOXC4, HOXC5, and HOXC6 in human lymphoid cell lines, leukemias, and benign and malignant lymphoid tissue. 863 19

Homeobox (HOX) genes are involved in the lineage-specific differentiation of bone marrow stem cells. Recently, we reported a largely similar expression pattern of HOXC4 and HOXC6 in normal and neoplastic cells of the lymphoid lineage. In contrast, HOXC5 was specifically expressed in a subset of B-cell non-Hodgkin's lymphomas (B-NHL) but not in normal lymphocytes or lymphoid leukemias. This might suggest a role for HOXC5 in the pathogenesis of these lymphomas. In the present study the expression of HOXC4, HOXC5, and HOXC6 in primary cutaneous lymphomas was investigated. Using RNA in situ hybridization (RISH) and semiquantitative reverse transcriptase polymerase chain reaction (RT-PCR), we found strong expression of HOXC4 and HOXC6 in all, except one, primary cutaneous lymphomas and all reactive cutaneous lymphoid infiltrates. Interestingly, a strong expression of HOXC5 in primary anaplastic CD30+ large T-cell lymphomas was found. RISH was consistently negative for HOXC5 in all other types of primary cutaneous B- and T-cell lymphomas. However, by semiquantitative RT-PCR these lymphomas showed a weak expression of HOXC5 mRNA. Therefore, we concluded that these lymphomas express low constitutive levels of HOXC5 mRNA. Furthermore, HOXC5 expression was consistently absent in reactive cutaneous lymphoid infiltrates, hyperplastic tonsils and lymph nodes, and peripheral blood lymphocytes either unstimulated or stimulated by a cocktail of CD3 and CD28 antibodies. As a strong expression of HOXC5 in primary cutaneous lymphomas was observed only in anaplastic large T-cell lymphomas and reactive control tissues lacked HOXC5 expression, these data strongly support a role for HOXC5 in the genesis of anaplastic large-T-cell lymphomas.
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PMID:HOXC4, HOXC5, and HOXC6 expression in primary cutaneous lymphoid lesions. High expression of HOXC5 in anaplastic large-cell lymphomas. 932 40

The spatial and temporal deployment of HOX homeobox genes along the spinal axis and in limb buds during fetal development is a key program in embryonic pattern formation. Although we have previously reported that several of the HOX homeobox genes are expressed during murine skin development, there is no information about developmental expression of HOX genes in human skin. We have now used reverse transcriptase polymerase chain reaction, in conjunction with a set of degenerate oligonucleotide primers, to identify a subset of HOX genes that are expressed during human fetal skin development. In situ hybridization analyses demonstrated that there were temporal and spatial shifts in expression of these genes. Strong HOXA4 expression was detected in the basal cell layers of 10 wk fetal epidermis and throughout the epidermis and dermis of 17 wk skin, whereas weak signal was present in the granular layer of newborn and adult skin. The expression patterns of HOXA5 and HOXA7 were similar, but their expression was weaker. In situ hybridization analysis also revealed strong HOXC4 and weaker HOXB7 expression throughout fetal development, whereas HOXB4 was expressed at barely detectable levels. Differential HOX gene expression was also observed in developing hair follicles, and sebaceous and sweat glands. None of the HOX genes examined were detected in the adult dermis.
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PMID:HOX homeobox genes exhibit spatial and temporal changes in expression during human skin development. 945 3