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D F Klessig

Publications and source records attributed to D F Klessig.

114 records · Page 7Linked to original sources
PubMed1978

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

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.

Adenoviruses, Human↗
PubMed1977

Two adenovirus mRNAs have a common 5' terminal leader sequence encoded at least 10 kb upstream from their main coding regions.

The messenger RNAs encoding two late adenovirus serotype 2 (Ad2) proteins, fiber and 100K, were purified by hybridization to restriction endonuclease fragments of Ad2 DNA followed by electrophoresis on polyacrylamide gels containing 98% formamide. The 5' terminal oligonucleotides generated by RNAase T1 digestion of the messengers were selected by dihydroxyboryl-cellulose chromatography. Both mRNAs gave an identical 5'-undecanucleotide with the general structure 7mG5'ppp5'AmC(m)U(C4,U3)G. This undecanucleotide could be removed by mild RNAase treatment from the mRNA after hybridization to DNA fragments containing the main coding sequence of the messenger. In contrast, a small region defined by Bal I-E (14.7-21) protects this undecanucleotide from RNase. A second region contained within both Hind III-B (17-31.5) and Hpa I-F (25.5-27.9), although unable to protect the undecanucleotide, hybridizes to both fiber and 100K mRNAs and protects a similar sequence of 100-150 nucleotides. These observations suggest that both mRNAs contain a long common sequence, complementary to at least two different sites on the Ad2 genome remote from the start of these two genes. The implications of these findings are discussed, and a general mechanism is presented for the biosynthesis of mRNAs from larger precursor molecules, based on intramolecular ligation.

Adenoviruses, Human↗
PubMed1977

Isolation of a variant of human adenovirus serotype 2 that multiplies efficiently on monkey cells.

A variant of adenovirus serotype 2 (Ad2) that overcomes the block to multiplication of the wild-type Ad2 on monkey cells is described. The variant was selected, after nitrous acid mutagenesis, by sequential passage on monkey cells. This variant forms plaques with similar efficiency on human and monkey cells cells. The kinetics of its growth and its burst size on human and monkey cells are similar. These growth properties are similar to those found for wild-type Ad2 on monkey cells when the block is overcome by coinfection with simian virus 40.

Adenoviruses, Human↗
PubMed1975

Block to multiplication of adenovirus serotype 2 in monkey cells.

The block to adenovirus 2 (Ad2) multiplication in monkey cells can be overcome by coinfection with simian virus 40 (SV40). To identify this block we have compared the synthesis of Ad2 proteins in monkey cells infected with Ad2 alone (unenhanced) or with Ad2 plus SV40 (enhanced). Synthesis of viral proteins in enhanced cells was virtually identical to that found for permissive infection of human cells by Ad2 alone. In contrast, the unenhanced cells were strikingly deficient in the production of the IV (fiber) and 11.5K proteins whereas the synthesis of 100K and IVa2 was normal. Synthesis of a number of other proteins such as II, V, and P-VII was partially reduced. A similar specific reduction in synthesis of these proteins was found when their messages were assayed by cell-free translation. This result suggests that the block to Ad2 protein synthesis is at the RNA level rather than with the translational machinery of monkey cells. Analysis of the complexity and the concentration of Ak2-specific RNAs, using hybridization of restriction endonuclease fragments of the Ad2 genome to increasing concentrations of RNA, shows that although all species of late Ad2 mRNA are present, the concentration of several species is reduced sevenfold or more in unenhanced monkey cells as compared with enhanced cells. These species come from regions of the genome known to encode the deficient proteins. A model for the failure of adenovirus to multiply in monkey cells, based on abnormal processing of specific adenovirus messages, is presented.

Adenoviridae↗
PubMedDate not supplied

Pathogenesis-related acidic beta-1,3-glucanase genes of tobacco are regulated by both stress and developmental signals.

Three pathogenesis-related (PR) proteins of tobacco are acidic isoforms of beta-1,3-glucanase (PR-2a, -2b, -2c). We have cloned and sequenced a partial cDNA clone (lambda FJ1) corresponding to one of the PR-2 beta-1,3-glucanases. A small gene family encodes the PR-2 proteins in tobacco, and similar genes are present in a number of plant species. We analyzed the stress and developmental regulation of the tobacco PR-2 beta-1,3-glucanases by using northern and western analyses and a new technique to assay enzymatic activity. Stress caused by both thiamine and tobacco mosaic virus (TMV) infection resulted in a dramatic increase in the levels of PR-2 mRNA, protein, and enzyme activities. The increased PR-2 gene expression in upper uninoculated leaves of plants infected with TMV also suggests a role in systemic acquired resistance. During floral development, a number of beta-1,3-glucanase activities were observed in all flower tissues. However, PR-2 polypeptides were observed only in sepal tissue. In contrast, an mRNA that hybridized to the PR-2 cDNA was present in stigma/style tissue and the sepals. Primer extension analysis confirmed the identity of the PR-2 mRNA in sepals, but indicated that the beta-1,3-glucanase gene expressed in the stigma/style of flowers was distinct from the PR-2 genes. The induction of PR-2 protein synthesis by both stress and developmental signals was accompanied by a corresponding increase in the steady-state levels of PR-2 mRNA, suggesting that PR-2 gene expression is regulated, in part, at the level of mRNA accumulation.

Amino Acid Sequence↗