The E1B 19-kilodalton protein is not essential for transformation of rodent cells in vitro by adenovirus type 5

Self Cite

mentioning

confidence: 99%

Constructing chimeric type 12/type 5 adenovirus E1A genes and using them to identify an oncogenic determinant of adenovirus type 12

Telling

Williams

1994

Self Cite

“…Growth characteristics of the inl virus in A549 and HeLa cells. Human A549 lung carcinoma cells (11) were used for growth and titration of AdS and in I and were derived from the stocks used in previous studies of El mutants (9,23,36). Human 293 cells (13) were used for growth of mutants defective in EIA and mutants defective in both EIA and 19K and for titration of AdS and its mutant viruses.…”

Section: Downloaded Frommentioning

confidence: 99%

“…The AdS wild-type strain was derived from the original seed stock used in all of our prior genetic studies with this serotype (14,46,47). The construction of the AdS inl mutant was described previously (36). It possesses a single AT-base-pair insert immediately following nucleotide (nt) 1715 in the E1B sequence, which destroys the proximal AUG present in E1B mRNAs and blocks production of intact E1B 19K protein in infected cells.…”

Section: Downloaded Frommentioning

confidence: 99%

“…respectively. At each stage in the construction of the EIA mutant viruses, the locations of the mutations or deletions of the introns were verified by doublestranded DNA sequencing of either plasmids or purified viral DNA (15), and digestion of the viral DNA with EcoNI was used to confirm the presence of the in I allele in the double mutants because the in I mutation destroys the EcoNI site normally located at nt 1710) in the E1B genome (36).…”

Section: Downloaded Frommentioning

confidence: 99%

See 1 more Smart Citation

Absence of an essential regulatory influence of the adenovirus E1B 19-kilodalton protein on viral growth and early gene expression in human diploid WI38, HeLa, and A549 cells

Telling

Perera

Szatkowski-Ozers

et al. 1994

Self Cite

Mutations in the gene encoding the adenovirus (Ad) early region 1B 19-kDa protein (the 19K gene) result in multiple phenotypic effects upon infection of permissive human cells. It has been reported, for example, that Ad type 2 (Ad2) and Ad5 with mutations in the 19K gene (19K-defective mutants) have a marked growth advantage compared with wild-type virus in human diploid W138 cells (E. White, B. Faha, and B. Stillman, Mol. Cell. Biol. 6:3763-3773, 1986), and it was proposed that this host range phenotype stems from the large increase in viral early gene expression reported to occur in the mutant-infected cells. These observations gave rise to the hypothesis that the 19-kDa protein (the 19K protein) normally functions as a negative regulator of Ad early gene expression and growth. We have tested this hypothesis and find that Ad5 and Adl2 wild-type viruses grow as efficiently as their respective 19K-defective mutants, inl and d1337 and pm700 and in700, in W138 and other human cell types. Neither the accumulation of ElA cytoplasmic mRNAs nor the synthesis of E1A and other viral early proteins in these cells is altered as a result of these mutations in the 19K gene, and we conclude that the 19K protein does not play an essential role in regulating viral early gene expression or viral growth in human cells.

“…The roles of 19K and 55K in transformation are still being investigated. Whether or not 19K is even necessary for transformation appears to be a controversy (1,2,4,8,12,36). The use of viral infections versus transfections and the use of many different cell types, both primary and established lines, have contributed to the conflicting results.…”

mentioning

confidence: 99%

Efficient nuclear localization and immortalizing ability, two functions dependent on the adenovirus type 5 (Ad5) E1A second exon, are necessary for cotransformation with Ad5 E1B but not with T24ras

Douglas

Quinlan

1995

Expression of adenovirus type 5 E1A 12S is sufficient to immortalize primary baby rat kidney cells, but another viral or cellular oncogene, such as E1B or T24ras, is necessary for complete transformation. The regions of 12S sufficient for T24ras cotransformation have been well characterized and are located in the first exon. The second exon is dispensable for ras cotransformation, although it contains a region which appears to modulate the transforming phenotype. The same 12S first exon regions important in ras transformation are also necessary for E1B transformation. Analysis of an extensive series of second exon deletion and amino acid point mutations demonstrated that mutations affecting either the efficient nuclear localization and/or the immortalizing ability of the 12S protein also prevented cooperation with E1B. In general, the entire C-terminal half of 12S, including the nuclear localization signal, was necessary for efficient cotransformation with E1B. In addition to the differences between T24ras and E1B regarding 12S regions necessary for cotransformation, the characteristics of E1B-cotransformed foci differed from those of T24ras. The E1B foci took longer to appear and had a much slower growth rate. No hypertransformed foci were produced with E1B cotransfections, and established E1A-E1B lines exhibited minimal growth in soft agar compared with that of E1A-T24ras lines.