Characterization of a variant of human adenovirus type 2 which multiples efficiently in simian cells

Abstract

In a previous report (Klessig, J. Virol. 21:1243-1246, 1977), the isolation of a variant (H2hr400) of adenovirus serotype 2 (Ad2) that overcomes the block to multiplication of wild-type Ad2 in simian cells was described. H2hr400 replicates efficiently on both human and simian cells, resulting in virus yields that are comparable to those found when wild-type Ad2 infects permissive, human cells. An extensive comparison of the genome of H2hr400 with that of its parent by restriction endonuclease, electron microscopic, and hybridization analyses failed to detect any differences and excludes the possibility that simian virus 40 sequences, which in certain Ad2-simian virus 40 hybrid viruses (e.g., Ad2+ND1) allow adenovirus to multiply efficiently in simian cells, are present in H2hr400. In contrast to Ad2, H2hr400 can fully express its late genes in both simian and human cells. The mutation has been mapped by a modified marker rescue technique to the segment of the viral genome located between coordinates 59 and 80.

Aberrant Distribution of Human Adenovirus Type 2 Late Proteins in Monkey Kidney Cells

“…As reported previously, fiber protein production was drastically reduced in Ad2-infected CV-C cells (9) but attained permissive levels after infection of CV-C cells with hr400 (Fig. 2, lane C) (12). The aberrant distribution of late proteins could be directly related to the reduction in the synthesis of particular late proteins.…”

The adenovirus type 2 DNA-binding protein interacts with the major late promoter attenuated RNA

“…Transcription, attenuation, mRNA transport-stability, and translation have all been implicated in reduced production of adenovirus (10, 13,14,26). This block can be overcome by a mutant adenovirus, hr400, whose mutation has been mapped to the DBP gene in the N-terminal domain in this protein (10,12,15). DBP was first described by its ability to bind to single-stranded DNA (11) but has recently been shown to also bind to RNA (1, 6).…”

“…In addition, the mRNA stability, transport, or translation of some adenovirus late family genes may be reduced (13). This block to productive infection can be relieved either by a helper function supplied by the carboxy-terminal fragment of the simian virus 40 large tumor antigen (7) or by a mutation localized in the adenovirus 72-kilodalton DNA-binding protein (DBP), as first described with the adenovirus type 2 (Ad2) mutant hr400 isolated by Klessig and his colleague (12,15). Studies of the detailed nature of the block for adenovirus late transcription in monkey cells have indicated that premature termination or attenuation can occur shortly after initiation of RNA synthesis at MLP (10).…”

Comparison of human and monkey cells for the ability to attenuate transcripts that begin at the adenovirus major late promoter

“…The human adenoviruses replicate poorly in most cell lines derived from African green monkey kidney cells (6). An important contribution to this block in the production of infectious virus is the reduction or inhibition of late viral gene transcription, in which some of the late gene families are more severely affected than others (6). This premature termination of transcription appears to occur more frequently during abortive infections of monkey cells than in productively infected cells (3).…”