UV-induced DNA damage is an intermediate step in UV-induced expression of human immunodeficiency virus type 1, collagenase, c-fos, and metallothionein.

Abstract

UV irradiation of human and murine cells enhances the transcription of several genes. Here we report on the primary target of relevant UV absorption, on pathways leading to gene activation, and on the elements receiving the UV-induced signal in the human immunodeficiency virus type 1 (HIV-1) long terminal repeat, in the gene coding for collagenase, and in the cellular oncogenefos. In order to induce the expression of genes, UV radiation needs to be absorbed by DNA and to cause DNA damage of the kind that cannot be repaired by cells from patients with xeroderma pigmentosum group A. UV-induced activation of the three genes is mediated by the major enhancer elements (located between nucleotide positions -105 and -79 of HIV-1, between positions -72 and -65 of the collagenase gene, and between positions -320 and -299 offos). These elements share no apparent sequence motif and bind different trans-acting proteins; a member of the NFKB family binds to the HIV-1 enhancer, the heterodimer of Jun and Fos (AP-1) binds to the collagenase enhancer, and the serum response factors p67 and p62 bind to fos. DNA-binding activities of the factors recognizing the HIIV-1 and collagenase enhancers are augmented in extracts from UV-treated cells. The increase in activity is due to posttranslational modification. While AP-1 resides in the nucleus and must be modulated there, NFKB is activated in the cytoplasm, indicating the existence of a cytoplasmic signal transduction pathway triggered by UV-induced DNA damage. In addition to activation, new synthesis of AP-1 is induced by UV radiation.Under severe stress, e.g., replication arrest by UV-induced DNA damage, many bacteria mount a productive response which involves the new synthesis of a large number of specific gene products (39, 74). The response has been named SOS (51), and it is triggered by the activation of preexisting recA protein and its increased synthesis, probably due to the interaction of recA protein with singlestranded regions of DNA (for a review, see reference 74).Mammalian cells in culture react to UV irradiation with a number of genetic changes resembling those in bacteria (for reviews, see references 29-31, 52, 60). These changes include the altered expression of specific genes (see B. Kaina, B. Stein, A. Schonthal, H. J. Rahmsdorf, H. Ponta, and P. Herrlich, in M. W. Lambert et al., ed., DNA Repair Mechanisms and Their Biological Implications in Mammalian Cells, in press, for a recent list of references). Many genes are induced, e.g., plasminogen activator (46), collagenase and metallothionein genes (2, 4), the cellular oncogene fos (5), and a human retrovirus, the human immunodeficiency virus type 1 (HIV-1) (B. Stein, cited in reference 29; 30, 69, 73).In an attempt to identify the elements of signal transduction to these genes, we show here that UV-induced gene expression is preceded by and requires absorption of UV radiation by DNA and UV-induced covalent DNA changes (photoproducts). Moreover, we define the DNA elements in three of the responsive genes (HIV-1, t...

Signal transduction through atypical PKCs, but not the EGF receptor, is necessary for UVC-induced AP-1 activation in immortal murine cells

“…This induction response includes transcriptional activation, repression of a speci®c expression of some genes, and induction of endogenous virus (Ronai et al, 1990;Angel, 1995). Based on studies with DNA repairde®cient Xeroderma pigmentosum cells (Schorpp et al, 1984;Stein et al, 1989) DNA damage or by-products have been hypothesized to provide the primary signal transduction pathways mediating u.v. response.…”

“…The exposure of mammalian cells to u.v. irradiation, including short (UVC, 200 ± 280 nM) and long (UVA, 320 ± 400 nM) wavelengths, as well as mid-wavelengths (UVB, 280 ± 320 nM), leads to a large number of changes in cells, such as activation of transcription factor AP-1 and NFkB and P53 (Stein et al, 1989;Devary, 1991;Ronai and Weinstein, 1988;. AP-1 (and another transcription factor, NFkB) has served to detect one of the decisive DNA binding motifs required for gene regulation by tumor promoters, such as 12-O-tetradecanoylphorbol-13-acetate (TPA), 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and u.v.…”

Characterization of a novel quiescence responsive element downregulated by v-Src in the promoter of the neuroretina specific QR1 gene

“…Reporter plasmids containing di erent deletions of the QR1 5'-¯anking sequences up to +55 with respect to the transcription start site, were transfected into tsPA101 infected QNR cells. CAT5 empty vector (Stein et al, 1989) and RSV/CAT (Gorman et al, 1982) were used as controls. CAT activity was measured at the permissive (378C: v-Src induced proliferation) and nonpermissive (418C: growth arrest) temperature.…”

“…C7 mutation was introduced into 71173/+55; 71265/+55 and 71265A7/+55 plasmids by PCR mediated mutagenesis. The 768/+55 minimal promoter sequence (mp) was obtained by PCR and inserted into the CAT5 vector (Stein et al, 1989) upstream from the CAT gene to give rise to mpCAT5 plasmid. To generate 71265/ 7935mpCAT5 constructs carrying A7 and/or C7 mutations, HindIII/BamHI fragments corresponding to the 71265/7935 region of QR1 promoter were excised from the appropriate 71265/+55 reporters and inserted into the mpCAT5 vector upstream from the minimal promoter.…”

“…Two plates were routinely transfected with the same reporter plasmid. CAT5 empty vector (Stein et al, 1989) and RSV/CAT (Gorman et al, 1982) were used as controls. After washing with phosphatebu ered saline and addition of fresh medium, plates were incubated 2 h at 378C.…”