标题：Mapping of linear and circular forms of mouse mammary tumor virus DNA with restriction endonucleases: evidence for a large specific deletion occurring at high frequency during circularization
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1978
卷号：75
期号：5
页码：2112-2116
DOI：10.1073/pnas.75.5.2112
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Rat hepatoma cells infected with mouse mammary tumor virus contain multiple forms of unintegrated viral DNA when grown in the presence of glucocorticoids. Using the DNA transfer procedure of Southern, we have prepared restriction endonuclease fragment maps of these forms of viral DNA. The maps indicate that: (i) the major species of viral DNA is a linear molecule of 5.9 X 10(6) Mr located in the cytoplasm; (ii) the nuclei contain covalently closed circular viral DNA of two distinct sizes (5.1 X 10(6) and 5.9 X 10(6) Mr) in addition to linear molecules (5.9 X 10(6) Mr); (iii) the linear molecule has specific termini; (iv) there is extensive homology between regions at or near termini of the linear molecule; (v) the predominant form of circular DNA lacks 1.2 kilobase pairs present in both the larger circular molecule and the linear molecule; and (vi) the sequences deleted from the majority of the circular DNA molecules are located at the ends of the linear DNA that are joined during circularization.
