Showing papers by "Phillip A. Sharp published in 1977"
TL;DR: A simple and sensitive method for detecting, sizing and mapping RNA transcripts from viral or cloned DNAs has been developed and used to examine the cytoplasmic transcripts produced during the early phase of adenovirus 2 (Ad2) infection of HeLa cells.
2,367 citations
TL;DR: Four segments of viral RNA may be joined together during the synthesis of mature hexon mRNA, a model is presented for adenovirus late mRNA synthesis that involves multiple splicing during maturation of a larger precursor nuclear RNA.
Abstract: An mRNA fraction coding for hexon polypeptide, the major virion structural protein, was purified by gel electrophoresis from extracts of adenovirus 2-infected cells late in the lytic cycle. The mRNA sequences in this fraction were mapped between 51.7 and 61.3 units on the genome by visualizing RNA-DNA hybrids in the electron microscope. When hybrids of hexon mRNA and single-stranded restriction endonuclease cleavage fragments of viral DNA were visualized in the electron microscope,branched forms were observed in which 160 nucleotides of RNA from the 5' terminus were not hydrogen bonded to the single-stranded DNA. DNA sequences complementary to the RNA sequences in each 5' tail were found by electron microscopy to be located at 17, 20, and 27 units on the same strand as that coding for the body of the hexon mRNA. Thus, four segments of viral RNA may be joined together during the synthesis of mature hexon mRNA. A model is presented for adenovirus late mRNA synthesis that involves multiple splicing during maturation of a larger precursor nuclear RNA.
1,229 citations
TL;DR: The concentration of early mRNAs observed in cells mixedly infected with unirradiated and irradiated virions suggests that initiation of transcription is the rate-limiting step in the production of the early m RNAs, and that this rate is independent of the number of viral templates within the nucleus.
88 citations
TL;DR: An attenuated bacteriophage lambda has been prepared for proposed use as an EK2 vector, and the rate of transfer of kanamycin resistance to permissive and nonpermissive strains of E. coli has been measured.
16 citations