An insertion mutation in the adenovirus type 12 early region 1A 13S mRNA unique region

Abstract

An adenovirus type 12 mutant, in203S, was constructed to contain an insertion of two amino acids in the early region 1A (E1A) 13S mRNA-coding region and in the ElA 12S mRNA intron. in203S could not grow in HeLa and KB cells. Virus DNA replication was scarcely detected at a low multiplicity of infection, but was detected at a high multiplicity of infection. The transcription of early genes other than ElA was not detected at 13 h after infection, but became detectable after longer incubation. The transcription of the ElA gene was also reduced to about one-fifth of the wild-type level. The mutant induced fewer foci of smaller sizes than the wild type in rat 3Y1 and secondary rat kidney cells. The induction of cellular DNA synthesis was reduced in rat 3Y1 cells infected with in2O3S as compared with that in wild type-infected cells. These results show that the EIA 13S mRNA-derived polypeptide of adenovirus type 12 is required for activation of early genes, cell transformation, and induction of cellular DNA synthesis.

Interferon induction by adenovirus type 12: stimulatory function of early region 1A

“…Adl2 in203S produces normal 12S mRNA but contains a 6-base-pair insertion coding two amino acids (Pro and Gly) in the 13S mRNA-coding region and the 12S mRNA intron (18). In Adl2 in2O3S-infected HeLa or KB cells, 13S-dependent early-viral-gene expression is not detected; therefore, the altered protein production of 13S mRNA is nonfunctional (18). However, in CEF cells, the IFN-inducing ability of Adl2 in203S was identical to that of Adl2 WT at multiplicities of infection of 1,000 (Fig.…”

“…Cells were cultured in Dulbecco modified Eagle medium supplemented with 10% fetal calf serum. Ad2 WT, AdS WT, Adl2 WT, Ad5 d1312 (gift of T. Shenk; 12), Ad5 rc-1 (22), Adl2 in203S (18), Ad12 d1203E10, and Adl2 d1203 (K. Shiroki, unpublished results) were used ( Table 1). Adenoviruses were purified by CsCl density gradient centrifugation as described previously (28).…”

“…The low level of ElA mRNA in Adl2 in203S-infected CEF cells is probably a consequence of the lack of an active A 28S -- 13S mRNA product, which has a positive regulatory function on ElA expression (18). In human cells, the transcription of the Adl2 in2O3S E1B region is also reduced markedly because of the lack of an active ElA 13S mRNA product (18). This effect could not be studied in CEF cells by Northern analysis, because the level of ElB-specific transcripts was extremely low even in Adl2 WT-infected cells.…”

Recombinant human adenoviruses containing hybrid adenovirus type 5 (Ad5)/Ad12 E1A genes: characterization of hybrid E1A proteins and analysis of transforming activity and host range

“…The 13S mRNA encodes a protein of 289 residues, containing 46 internal amino acids not present in the 243-residue protein encoded by the 12S mRNA. This unique region is responsible for the transcriptional activation of other viral genes and some cellular genes (3,5,18,30,(37)(38)(39)46). Stable expression of ElA proteins can immortalize cultured primary rodent cells (28,47) and, in cooperation with ElB or other oncogenes such as ras, can induce oncogenic transformation (43).…”

Activation of the human beta interferon gene by the adenovirus type 12 E1B gene

“…region (1,536 to 3,858 bp) (11). gdl7-9ElB is gApB with a deletion of 852 bp in the 58K region (17).…”