Generation of a nucleosome-free promoter region in SV40 does not require T-antigen binding to site I.
The relationship between T-antigen interactions at Site I and the presence of a nucleosome-free promoter in SV40 chromatin was examined by analyzing chromatin from mutants defective for T-antigen interaction at site I (cs 1085, scs111, and tsA58) and their parental wild-type strains (776, SVS, and VA45-54, respectively). As judged by sensitivity to digestion with restriction endonucleases that recognize unique sequences within the promoter region (BglI, KpnI, and MspI), a nucleosome-free promoter was observed in a substantially larger proportion of chromosomes from the defective mutants than their wild-type parents. This result demonstrates that T-antigen binding to site I is not necessary for setting the early boundary of the nucleosome-free region, although it may function directly or indirectly in determining the proportion of chromosomes containing this feature.
Kube
D
D
Department of Biochemistry and Molecular Biology, University of North Dakota School of Medicine, Grand Forks 58202.
Milavetz
B
B
D000952:Antigens, Polyomavirus Transforming / Q000502:physiology*; D001665:Binding Sites; D002460:Cell Line; D004252:DNA Mutational Analysis; D005786:Gene Expression Regulation; D009707:Nucleosomes / Q000502:physiology*; D011401:Promoter Regions, Genetic; D015183:Restriction Mapping; D013539:Simian virus 40 / Q000235:genetics*
D000952:Antigens, Polyomavirus Transforming; D009707:Nucleosomes