Adenovirus DNA replication

Rosenfeld and Kelly (1) purified Nuclear Factor-I (NF-I), a Hela cell protein that enhances initiation of adenovirus DNA replication vitro, by affinity chromatography on a specific DNA-cellulose column. The column was prepared by adsorption to cellulose of a plasmid engineered to contain multiple (88) copies of the binding site for NF-1. NF-1 was purified from a Hela cell nuclear extract by chromatography on Bio-rex 70, coli DNA-cellulose, and two sequential passes on the specific DNA affinity column. 

Challberg, M. D., Desiderio, S. V., and Kelly, T. J., 1980, Adenovirus DNA replication in vitro Characterization of a protein covalently linked to nascent DNA strands, Proc. Natl., Acad. Sci. USA 77 5105. 

Enomoto, T., Lichy, J. H., Ikeda, J. E., and Herwitz, J., 1981, Adenovirus DNA replication in vitro Purification of the terminal protein in a functional form, Proc. Natl. Acad. Sci. USA 78 6779. 

Nagata, K., Guggenheimer, R. A. and Hurwitz, J., 1983, Adenovirus DNA replication in vitro Synthesis of full length DNA with purified proteins, Proc. Nat. Acad. Sci. USA 80 4266. 

Lithium (at 40 mM) inhibits the replication of herpes virus, pox virus, and adenovirus (DNA viruses) but does not inhibit that of RNA viruses such as influenza virus or encephalomyocarditis virus (209). 

The most extensively used adenoviruses are serotypes 2 (Ad2) and 5 (Ad5) because both are not associated with serious infectious disease in humans. - Similar to retroviral vectors, elements of adenovirus DNA genome are removed to prevent replication once inside the... 

Yet another solution to this problem is used by some viruses. Phage < )29 of Bacillus subtilis primes the replication of its 19,285 bp dsDNA at both ends by a terminal protein, which is linked covalently through its Ser 232 - OH group to dAMP. The 3 -OH of the deoxyadenosyl group primes the DNA replication. In a similar fashion replication of the eukaryotic adenoviruses, whose genome is a 35- to... 

While the poly (A) sequences do seem to be involved in the transport of mRNA s from the nucleus, this does not seem to be the sole function of the poly (A) tract for example, adenovirus DNA appears to lack a DNA sequence complementary to poly (A) but replicates in the nucleus of the mammalian cell and appears to have a poly (A) tract added to the viral mRNA by host-cell mechanisms for transport of the adenovirus mRNA to the cytoplasm (Philipson et ah, 1971). As with cellular messages, cordycepin blocks both the labeling of the poly (A) tracts and the appearance of adenovirus-specific RNA in the cytoplasm of infected cells (Philipson et ah, 1971). In contrast, vaccinia virus replicates exclusively in the cytoplasm of cells it infects and still contains poly(A) sequences (Kates, 1970). Since no role in transport is involved here, it suggests that some mRNAs may require a poly (A) sequence for proper translation. Further, not all mammalian mRNAs contain poly (A) and still are transported to the cytoplasm for translation. Specifically, the 9 S histone message isolated by Adesnik and Darnell (1972) from HeLa cells lacks any detectable poly (A) sequence of any significant length. These workers have also shown that the exit time of the histone mRNA molecule from the nucleus is shorter than that of other messenger RNA s. 

The best known response of cellular DNA synthesis to adenovirus infection must be the inhibition typically seen when permissive human cells are infected. In growing cells, cellular DNA synthesis is inhibited by more than 50% by 6-8 hr and completely by 10-13 hr after an adenovirus infection (Ginsberg et al., 1967), concomitant with the initiation and acceleration of viral DNA synthesis. Unfortunately, very few studies have concentrated on elucidation of this inhibitory process. Hodge and Scharff (1969) presented some evidence to suggest that initiation of new rounds of cellular DNA synthesis was prevented by adenovirus infection. Thus, when synchronized human cells were infected at a time in their cell cycle that placed viral DNA replication in the G1 phase, neither premature, nor normal S phase, initiation of cellular DNA synthesis were observed. Alternatively, infection to place initiation of viral DNA synthesis after the onset of the host cells S phase permitted completion of those rounds of cellular DNA synthesis begun before the inhibitory mechanism exerted... 

Shiroki, K., and Shimojo, H., 1975, Analysis of adenovirus 12 temperature-sensitive mutants defective in viral DNA replication. Virology 61 674. 

AAV-specific RNA synthesis does not precede AAV DNA synthesis (Rose and Koczot, 1972). AAV RNA synthesis is first detectable approximately 2 hours after the onset of AAV DNA synthesis when AAV and adenovirus are used simultaneously to infect a cell. This is true even under conditions where adenovirus early messenger RNA synthesis is readily measurable. Thus the possibility exists that there is no class of AAV RNA synthesized prior to the onset of DNA replication. Again, if adenovirus infection preceded AAV infection by 10 hours, AAV-specific RNA could be detected starting at Shours after AAV infection at the time of onset of AAV DNA synthesis (Carter et al, 1973). 

Additional viruses that may prove of some use as future viral vectors include adeno-associated virus and herpes virus. Adeno-associated virus is a very small, single-stranded DNA virus its genome consists of only two genes. It does not have the ability to replicate autonomously and can do so only in the presence of a co-infecting adenovirus (or other selected viruses). 

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