Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.30.1 (S1 nuclease)
 3,660 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The structure of the murine interleukin-4 receptor (mIL-4R) gene has been determined. The gene spans approximately 25 kilobases (kb) of DNA and is composed of 12 exons interrupted by 11 introns. The gene contains sequences accounting for all the sequences present in the functional mIL-4R cDNAs, including several exons which can encode DNA inserts found in recently cloned IL-4R cDNA variants. Thus expression of the gene may be regulated, at least in part, by alternative splicing. A combination of S1 nuclease protection and primer extension assays was used to localize the 5' end of the gene and demonstrated the use of multiple transcription initiation sites within this region. We have found that the overall intron-exon organization of the murine IL-4R gene is markedly similar to that of the murine erythropoietin receptor (m-epoR) and the human interleukin-2 receptor beta chain (hIL-2R beta), as well as the human growth hormone receptor (hGhR). This is consistent with the recent grouping of these receptors, on the basis of protein sequence homology, into the hematopoietin receptor gene superfamily. Such homology at the levels of both protein and gene structure suggest a divergent evolution of the receptors from a single primordial gene.
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PMID:The murine interleukin-4 receptor gene: genomic structure, expression and potential for alternative splicing. 153 14

B cells can be activated by T-independent antigens or mitogens such as lipopolysaccharide (LPS) which will induce proliferation and differentiation of the B cells into Ig-secreting cells, without the intervention of T cells. The precise mechanism of T-independent proliferation and differentiation of B cells is still unclear. It is possible however that antigen-stimulated B cells may produce some factors which play a role in T-independent B-cell responses. In addition, since it has now been established that B cells can function as antigen-presenting cells, it is possible that they too secrete a molecule which is involved in the activation of T cells, analogous to IL-1 production by antigen-presenting macrophages. A number of human B-cell lines, as well as human normal B cells activated appropriately, have been shown to produce various cytokines, and similar studies are now being undertaken in the mouse. In the present study, six cloned murine B-cell lymphomas of different origin were analyzed for the presence of mRNA encoding a number of lymphokines by hybridization of specific cDNA probes to poly-A RNA, followed by the sensitive S1 nuclease digestion technique. The lymphokines included (IL-) 1, 2, 3, 4, 5, and neuroleukin. Whereas none of the lines expressed detectable levels of IL-2, IL-3, or IL-5 mRNA, all the lines expressed high levels of neuroleukin mRNA. Three of the lymphomas (CH12, CH31, and NBL) expressed low levels of IL-1 mRNA. The most striking finding was that one lymphoma, CH12, constitutively expressed IL-4 mRNA. This mRNA appeared to be functional, as IL-4 activity measured by the HT-2 T cell proliferation assay could be detected in supernatants collected from CH12 cells. The growth-inducing activity of CH12 supernatant on HT-2 cells could be completely blocked by an anti-IL-4 monoclonal (11B11), but not by an anti-IL-2 antibody (S4B6), consistent with our observations that CH12 cells produce IL-4 but not IL-2. CH12 cells were also found to express high affinity receptors for IL-4. Proliferation of CH12 cells was not affected by the addition of exogenous IL-4. Addition of anti-IL-4 antibodies to CH12 cells in culture caused a slight but reproducible increase in their proliferation at low cell numbers, which is probably not highly significant. These findings open the possibilities that murine B lymphocytes are capable of lymphokine production or alternatively that aberrant lymphokine production underlies B-lymphocyte transformation.
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PMID:Constitutive production of lymphokines by cloned murine B-cell lymphomas--CH12 B lymphoma produces interleukin-4. 278 29