Interspersion of mouse satellite deoxyribonucleic acid sequences.
DNA sequences with homology to the major (A + T)-rich mouse satellite component were localized in CsCl gradients by hybridization with a labeled satellite cRNA probe. Although, as expected, most of the hybridization was to DNA in the satellite-rich shoulder, substantial radioactive cRNA hybridized with DNA from denser regions of the gradient. Further examination revealed that hybridization to main-band DNA was not due to physical trapping of satellite DNA in the gradient, and melting experiments argue that the associated radioactivity was due to true RNA/DNA hybridization. Nearest-neighbor analysis of hybridized [alpha-32P]CTP-labeled l-strand cRNA indicates that hybridization to main-band DNA is by the satellite cRNA and not a contaminant. Together, these data argue that mouse satellite-like sequences are interspersed within the main-band fraction of DNA. For the support of this contention, total mouse DNA, purified main-band DNA, and purified satellite DNA were digested with EcoRI, sedimented in a sucrose gradient, and hybridized with labeled satellite cRNA. Mouse satellite DNA is not cleaved with EcoRI, so that purified EcoRI-digested satellite DNA sediments as a high molecular weight component. When total mouse DNA is digested with EcoRI, the majority of satellite-like sequences remain as high molecular weight DNA; however, significant amounts of satellite-like sequences sediment with the bulk of the lower molecular weight digested DNA, lending further credence to the argument that satellite-like sequences are interspersed with main-band DNA.
D000818:Animals; D001483:Base Sequence; D002499:Centrifugation, Density Gradient; D004247:DNA / Q000302:isolation & purification; D004262:DNA Restriction Enzymes; D004276:DNA, Satellite / Q000302:isolation & purification; D007700:Kinetics; D008099:Liver / Q000032:analysis*; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D009693:Nucleic Acid Hybridization
D004276:DNA, Satellite; D004247:DNA; D004262:DNA Restriction Enzymes