Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.1.26.4 (RNase H)
 2,751 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We previously showed that the in vitro transcription of a negatively supercoiled plasmid containing the murine IgA switch region caused the formation of fewer supercoiled conformers of the plasmid due to the presence of a stable RNA.DNA hybrid. Here, we demonstrate that the RNA.DNA hybrid is approximately 140 nucleotides, and it forms regardless of the initial topological state of the transcription template. Transcription of the switch region in a relaxed closed circular plasmid generates positively supercoiled plasmid conformers that revert to their original relaxed state when treated with RNase H. Conformers that have incorporated a stable RNA transcript are also observed when nicked circular and linear plasmids containing the IgA switch sequences are transcribed with 32P-labeled nucleotide triphosphates. Once formed, the RNA.DNA hybrid is stable to both thermal and superhelical stress, tolerating temperatures in excess of 95 degrees C and restraining approximately 12 positive supercoils in the plasmid.
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PMID:Transcription induces the formation of a stable RNA.DNA hybrid in the immunoglobulin alpha switch region. 806 29

Virally regulated HIV-1 particles were expressed from DNA plasmids encoding Gag, protease, reverse transcriptase, Vpu, Tat, Rev, and Env. The sequences for integrase, Vpr, Vif, Nef, and the long terminal repeats (LTRs) were deleted. Mutations were engineered into the VLP genome to produce particles deficient in activities associated with viral reverse transcriptase, RNase H, and RNA packaging. Each plasmid efficiently secreted particles from primate cells in vitro and particles were purified from the supernatants and used as immunogens. Mice (BALB/c) were vaccinated intranasally (day 1 and weeks 3 and 6) with purified VLPs and the elicited immunity was compared to particles without Env (Gag(p55)), to soluble monomeric Env(gp120), or to soluble trimerized Env(gp140). Only mice vaccinated with VLPs had robust anti-Env cellular immunity. In contrast, all mice had high titer anti-Env serum antibody (IgG). However, VLP-vaccinated mice had antisera that detected a broader number of linear Env peptides, had anti-Env mucosal IgA and IgG, as well as higher titers of serum neutralizing antibodies. VLPs elicited high titer antibodies that recognized linear regions in V4-C5 and the ectodomain of gp41, but did not recognize V3. These lentiviral VLPs are effective mucosal immunogens that elicit broader immunity against Env determinants in both the systemic and mucosal immune compartments than soluble forms of Env.
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PMID:Membrane embedded HIV-1 envelope on the surface of a virus-like particle elicits broader immune responses than soluble envelopes. 1701 Oct 11