title: Expression and demethylation of germinally-transmitted BALB/c mouse mammary tumor virus DNA in Abelson MuLV B-lymphoid cell lines.
abstract: Murine mammary tumor virus (MMTV) RNA expression, DNA organization and DNA demethylation were examined in BALB/c B-lymphoid cell lines produced by transformation with the Abelson murine leukemia virus (AbMuLV). The MMTV DNA sequences in AbMuLV B cell lines, based on restriction mapping with EcoRI, PstI, BglII, BamHI and SacI and molecular hybridization with cloned probes of the MMTV LTR, gag-pol or env gene regions, were identical to the germinally-transmitted MMTV DNA complement of BALB/c mice. Several AbMuLV B cell lines expressed MMTV poly(A+)-RNA at detectable levels. MMTV poly(A+)-RNA for the env gene, 3.8 kb, and the long terminally redundant (LTR) region, 1.7 kb, were detected in some AbMuLV B cell lines. MMTV DNA sequences in the AbMuLV B cell lines were at least partially sensitive to digestion by the methylation-sensitive restriction endonucleases HhaI and HpaII. HhaI-sensitive sites were present in Units I, II and III of the germinally-transmitted MMTV DNA and were localized specifically near the 5' end of the 5' and 3' LTRs of both Units II and III. HpaII-sensitive sites were localized near the 3' end of the 3' LTRs of Units II and III, and at a cellular site 2.1 kbp 5' to the 5' LTR. These observations demonstrate that the germ line MMTV DNA sequences of BALB/c mice are expressed in cells of B lymphocyte origin, and suggest a correlation between MMTV RNA expression and selective demethylation in the LTR regions of germinally-transmitted MMTV DNA sequences.
mesh_terms: D000011:Abelson murine leukemia virus; D000818:Animals; D001402:B-Lymphocytes / Q000382:microbiology*; D001483:Base Sequence; D002460:Cell Line; D004262:DNA Restriction Enzymes / Q000494:pharmacology; D004279:DNA, Viral / Q000032:analysis* / Q000378:metabolism; D003640:Dealkylation; D005260:Female; D007942:Leukemia, Experimental / Q000382:microbiology; D008324:Mammary Tumor Virus, Mouse / Q000235:genetics* / Q000276:immunology; D051379:Mice; D008807:Mice, Inbred BALB C; D009693:Nucleic Acid Hybridization; D012367:RNA, Viral / Q000032:analysis
chemical_list: D004279:DNA, Viral; D012367:RNA, Viral; D004262:DNA Restriction Enzymes