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：1974
卷号：71
期号：9
页码：3545-3549
DOI：10.1073/pnas.71.9.3545
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：We have developed an in vitro complementation assay to demonstrate packaging and maturation of DNA of phage T7. Cells of Escherichia coli B infected with an appropriate T7 amber mutant are concentrated 200-fold and lysed by freezing and thawing. Two extracts from cells infected with different amber mutants are mixed and incubated at 30{degrees}. Positive complementation results in a 100-fold increase in phage titer. Using this assay we have demonstrated the packaging of phage DNA from an extract that contains no phage heads (gene 9-, 10-), within head structures present in an extract that contains no phage DNA (gene 5-). We have also demonstrated an activity in extracts that contain no phage DNA or heads (gene 5-, 9-, 10-), which complements gene 19--infected cells. We have proven that this activity is due to the gene-19 product by showing that the activity is temperature-sensitive if the extract is made from cells infected with a mutant having a temperature-sensitive mutation in gene 19. This assay should be useful in elucidating the mechanism of packaging and maturation of DNA of phage T7.
