Requirement of the human chromosome 11 long arm for replication of herpes simplex virus type 1 in nonpermissive Chinese hamster x human diploid fibroblast hybrids

A subset of xeroderma pigmentosum (XP) group E cells lack a factor that binds to DNA damaged by UV radiation. This factor can be purified to homogeneity as p125, a 125-kDa polypeptide. However, when cDNA encoding p125 is translated in vitro, only a small fraction binds to UV-damaged DNA, suggesting that a second factor is required for the activation of p125. We discovered that most hamster cell lines expressed inactive p125, which was activated in somatic cell hybrids containing human chromosome region 11p11.2-11cen. This region excluded p125 but included p48, which encodes a 48-kDa polypeptide known to copurify with p125 under some conditions. Expression of human p48 activated p125 binding in hamster cells and increased p125 binding in human cells. No such effects were observed from expression of p48 containing single amino acid substitutions from XP group E cells that lacked binding activity, demonstrating that the p48 gene is defective in those cells. Activation of p125 occurred by a "hit-and-run" mechanism, since the presence of p48 was not required for subsequent binding. Nevertheless, p48 was capable of forming a complex with p125 either bound to UVdamaged DNA or in free solution. It is notable that hamster cells fail to efficiently repair cyclobutane pyrimidine dimers in nontranscribed DNA and fail to express p48, which contains a WD motif with homology to proteins that reorganize chromatin. We propose that p48 plays a role in repairing lesions that would otherwise remain inaccessible in nontranscribed chromatin.

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“…To identify this activating gene, binding activity was measured in several hamster-human hybrid cell lines (13,14,28,31) (Fig. 4A).…”

Section: Resultsmentioning

confidence: 99%

p48 Activates a UV-Damaged-DNA Binding Factor and Is Defective in Xeroderma Pigmentosum Group E Cells That Lack Binding Activity

Hwang

Toering²,

Francke

et al. 1998

Molecular and Cellular Biology

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147

156

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“…Chromosome mapping was done first by Southern blot analysis of DNA from Chinese hamster x human somatic hybrid cell lines (9)(10)(11)(12). BglII-digested DNA (10 ,ug per lane) was separated by electrophoresis, transferred to nitrocellulose, and hybridized with rat brain a-spectnn probe (RBF2) or the human probe (NBF1) as described previously (1).…”

Section: '-3'mentioning

confidence: 99%

Comparison of nonerythroid alpha-spectrin genes reveals strict homology among diverse species.

Leto¹,

Fortugno-Erikson²,

Barton³

et al. 1988

Mol. Cell. Biol.

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The spectrins are a family of widely distributed filamentous proteins. In association with actin, spectrins form a supporting and organizing scaffold for cell membranes. Using antibodies specific for human brain alpha-spectrin (alpha-fodrin), we have cloned a rat brain alpha-spectrin cDNA from an expression library. Several closely related human clones were also isolated by hybridization. Comparison of sequences of these and other overlapping nonerythroid and erythroid alpha-spectrin genes demonstrated that the nonerythroid genes are strictly conserved across species, while the mammalian erythroid genes have diverged rapidly. Peptide sequences deduced from these cDNAs revealed that the nonerythroid alpha-spectrin chain, like the erythroid spectrin, is composed of multiple 106-amino-acid repeating units, with the characteristic invariant tryptophan as well as other charged and hydrophobic residues in conserved locations. However, the carboxy-terminal sequence varies markedly from this internal repeat pattern and may represent a specialized functional site. The nonerythroid alpha-spectrin gene was mapped to human chromosome 9, in contrast to the erythroid alpha-spectrin gene, which has previously been assigned to a locus on chromosome 1.

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“…CHO cells do not support HSV replication (2). Little attention has been focused on determining whether HSV can enter CHO cells to initiate viral gene expression.…”

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confidence: 99%

Fibroblast Growth Factor Receptor: Does It Have a Role in the Binding of Herpes Simplex Virus?

Shieh

Spear

1991

Science

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We found that purified radiolabeled HSV could bind as well or better to the FGF receptor-deficient A-1 cells as they could to the FGF receptor-positive 4-1 cells (Fig. 1). At every concentration, about twice as much virus bound per cell to the A-1 cells as to the 4-1 cells, in the absence of heparin. The binding was inhibited by heparin, as has been shown previously for the binding of HSV to permissive HEp-2 cells (6). Because the adsorption of HSV to cells requires the presence of cell surface heparan sulfate (6), these results suggest that the faster growing 4-1 cells may express less cell surface heparan sulfate than do the control A-i cells. At the highest dose of virus tested in Fig. 1, which was not sufficient to saturate receptors for HSV, the amount ofvirus bound to the A-1 cells was about 1,800 plaque-forming units (PFU) per cell or 36,000 particles per cell. We estimate that the amount of virus required to saturate HSV receptors on permissive HEp-2 cells is 60,000 particles per cell (7). Therefore, the ability of the FGF receptor-deficient CHO cells to bind HSV may be similar to that of permissive HEp-2 cells.We also quantitated the adsorption of radiolabeled HSV to both cell lines at 370Cand determined the susceptibility of the cells to abortive infection by monitoring expression of the immediate-early HSV protein designated iCP4. Adsorption of virus was similar for the A-i and the 4-1 cells, and the two cell lines were indistinguishable with respect to the fraction of cells that expressed ICP4 (Fig. 2)

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Requirement of the human chromosome 11 long arm for replication of herpes simplex virus type 1 in nonpermissive Chinese hamster x human diploid fibroblast hybrids

Cited by 33 publications

References 28 publications

p48 Activates a UV-Damaged-DNA Binding Factor and Is Defective in Xeroderma Pigmentosum Group E Cells That Lack Binding Activity

p48 Activates a UV-Damaged-DNA Binding Factor and Is Defective in Xeroderma Pigmentosum Group E Cells That Lack Binding Activity

Comparison of nonerythroid alpha-spectrin genes reveals strict homology among diverse species.

Fibroblast Growth Factor Receptor: Does It Have a Role in the Binding of Herpes Simplex Virus?

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