Functional diversity of E1A gene autoregulation among human adenoviruses

Abstract

Autoregulation of the adenovirus EIA gene involves its constitutive expression and positively and negatively regulated transcription. Dissection of this process will identify basal-level cis elements and autoregulatory targets of the ElA promoter and functional domains within the transacting ElA gene products. In this report, the DNA sequence of the human subgroup B adenovirus type 3 (Ad3) ElA gene is presented and compared with that of the EIA genes of similar and distantly related human adenoviruses. The cDNA forms of the Ad3 ElA gene, corresponding to two major early mRNA species, are cloned, sequenced, and subcloned into plasmid expression vectors. Cotransfections of cell cultures are performed with Ad5 or Ad3 ElA gene expression plasmids and a reporter gene under control of the Ad5 or Ad3 ElA promoter. The Ad5 and Ad3 ElA promoters are similarly repressed by either serotype's 12S cDNA gene products. The Ad3 ElA promoter responds much more strongly than the AdS EIA promoter to transactivation by 13S cDNA gene products. In contrast, the 13S cDNA gene of Ad5 has greater transactivation activity than that of Ad3. Experiments with missense mutations

The nucleotide sequence and a first generation gene transfer vector of species B human adenovirus serotype 3

“…The 136 bp ITR sequence reported here is identical to the sequence reported earlier for human Ad3 (Tolun et al, 1979), except for a G -C mismatch at position 91. Two further sequence determinations (Kosturko et al, 1982;Cogan et al, 1992) confirmed our sequencing at this location (note that the sequence reported by Cogan is not available in electronic format). The entire Ad3 ITR sequence is very similar to the 136 bp ITR of the closely related Ad7 (Greiner strain) (Shinagawa and Padmanabhan, 1980), except for seven mismatches.…”

“…The E1A proteins are the major transactivators controlling viral replication. The putative splice variants of Ad3 13S, 12S, and 9S of E1A were mapped according to previously published sequences for the Ad3 E1 region (Avvakumov et al, 2002;Cogan et al, 1992), the latter perfectly matching the herein described sequence (Table 1). Similar E1A ORFs have been described for other B species serotypes including Ad7 (Dijkema et al, 1980;Purkayastha et al, 2005b), Ad11 (Mei et al, 2003;Stone et al, 2005), and Ad35 (Gao et al, 2003).…”