Multiple mRNA species generated by alternate polyadenylation from the rat manganese superoxide dismutase gene

Hurt, Jonathan D.; Hsu, Jan-Ling; Dougall, William C.; Visner, Gary; Burr, Ian M.; Nick, Harry S.

doi:10.1093/nar/20.12.2985

Cited by 64 publications

(35 citation statements)

References 28 publications

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“…The steady-state levels of Mn-SOD RNA are much lower in HeLa-tat cells than in the parental cells. The multiple transcripts seen have been ascribed to alternative polyadenylylation signals (34). Cu,Zn-SOD RNA levels were the same in both cell types.…”

Section: Resultsmentioning

confidence: 87%

Tat protein of human immunodeficiency virus type 1 represses expression of manganese superoxide dismutase in HeLa cells.

Flores

Marecki

Harper

et al. 1993

Proc. Natl. Acad. Sci. U.S.A.

198

131

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Using a HeLa cell line stably transfected with the tat gene from human immunodeficiency virus type 1, we have found that the expression of the regulatory Tat protein suppresses the expression ofcellular Mn-containing superoxide dismutase (Mn-SOD). This enzyme is one of the cell's primary defenses against oxygen-derived free radicals and is vital for maintaining a healthy balance between oxidants and antioxidants. The parental HeLa cells expressed nearly equivalent amounts of Cu,Zn-and Mn-SOD isozymes. Those cels expressing the Tat protein, however, contained 52% less Mn-SOD activity than parental cells, whereas that of the Cu,Zn enzyme was essentially unchanged. The steady-state levels of Mn-SOD-specific RNAs were also lower in the HeLa-tatcell line than in the parental line. No difference was seen in the steady-state levels of Cu,Zn-SOD-specific RNAs. In addition to the decreased Mn-SOD activity, HeLa-tatceDls showed evidence of increased oxidative stress. Carbonyl proteins were markedly higher, and total cellular sulfhydryl content decreased in ceDl extracts at a faster rate, probably reflecting ongoing lipid peroxidation. HeLa and HeLa-tat extracts were incubated with radiolabeled Mn-SOD transcripts, and the reaction products were subjected to UV crosslinking, digestion with ribonuclease A, and electrophoretic analysis. The results suggest a direct interaction between Tat protein and Mn-SOD gene transcripts.

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Section: Resultsmentioning

confidence: 87%

Tat protein of human immunodeficiency virus type 1 represses expression of manganese superoxide dismutase in HeLa cells.

Flores

Marecki

Harper

et al. 1993

Proc. Natl. Acad. Sci. U.S.A.

198

131

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“…Endogenous MnSOD mRNA Half-life-We have previously reported that the five transcripts of rat MnSOD mRNA observed on steady state Northern analysis arise from alternative polyadenylation of the primary transcript (29). Work from our laboratory has also shown that each of the mRNA species are induced and degraded similarly in response to proinflammatory mediators (14).…”

Section: Resultsmentioning

confidence: 98%

“…Plasmid Construction-MnSOD fragments were amplified by polymerase chain reaction from a previously characterized MnSOD cDNA (29) using standard conditions and primers specific to appropriate 5Ј and 3Ј termini. Products are denoted by their position relative to the translational initiation site (ϩ1) of the MnSOD cDNA (Fig.…”

Section: Methodsmentioning

confidence: 99%

A Coding Region Determinant of Instability Regulates Levels of Manganese Superoxide Dismutase mRNA

Davis¹,

Monnier²,

Nick³

2001

Journal of Biological Chemistry

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The mitochondria-localized manganese superoxide dismutase (MnSOD), serves a key cytoprotective role against reactive oxygen species arising from a variety of cellular processes and immunological stresses. Previous data from our laboratory suggest that the regulation of the rat MnSOD gene may occur not only at the transcriptional but quite possibly at the post-transcriptional level. To verify this hypothesis, we have attempted to identify regions within the rat MnSOD cDNA that may be functionally involved in regulating the stability of the mRNA. Using a c-fos-based promoter activation system, we have identified an ϳ280-nucleotide fragment within the MnSOD mRNA coding region that, when fused to a rabbit ␤-globin gene, destabilizes the normally stable ␤-globin mRNA. This cis-directed destabilization phenomenon confers its effects independent of position and stimulus. Most importantly, the MnSOD coding region determinant functions when placed in the 3-untranslated region of the ␤-globin transcript, demonstrating its activity in the absence of ribosome transit. We feel that these data provide a mechanistic basis for both the basal and stimulus-dependent post-transcriptional regulation of MnSOD.Regulated levels of antioxidant enzymes provide an initial level of cellular defense against damaging reactive oxygen species. The nucleus-encoded mitochondria-localized manganese superoxide dismutase (MnSOD) 1 is one such enzyme providing potent cytoprotection against a variety of challenges. In addition to reversing the malignant phenotypes of specific carcinomas (1), overexpression of MnSOD has been shown to protect against exposure to radiation (2, 3), cytokines (4, 5), chemotherapeutic agents (6), ischemia/reperfusion (7), and glutamatedependent neurotoxicity (8). Gene ablation studies generating MnSOD (Ϫ/Ϫ) mice have demonstrated the physiological importance of this enzyme. Depending on the background strain used, homozygote MnSOD (Ϫ/Ϫ) mice develop severe cardiomyopathy (9) or neurological abnormalities (10), with death resulting within 10 days or 3 weeks of birth, respectively.Several laboratories, including our own, have provided insights into the molecular regulation of the MnSOD gene through promoter elements (11) and the identification of a bacterial endotoxin and cytokine-specific intronic enhancer element (12, 13). Nuclear run-on analysis following induction with proinflammatory mediators (11) does not reflect a complete recapitulation of induced levels of RNA observed in steady-state Northern analysis, inferring a relevant role for RNA stability in the molecular regulation of MnSOD. Interestingly, induced MnSOD transcripts do not return to basal levels following treatment with actinomycin D or cycloheximide, suggesting the involvement of de novo transcription and translation in the turnover of the message (14). These data implicate the existence and potential importance of an underlying mechanism controlling MnSOD mRNA half-life in both the basal and stimulated expression of this gene.Modulations in mRNA stabil...

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“…Each of these mRNA transcripts has been shown to give rise to mature, functional protein (Hurt et al, 1992). MnSOD rnRNA levels (figure 12A) in both control and CSH-treated astrocytes increased in parallel between 0 and 12 hours foUowing initiation of the treatment.…”

Section: Northern B10ts For Mnsodmentioning

confidence: 99%

Differential effects of cysteamine on heat shock protein induction and cytoplasmic granulation in astrocytes and glioma cells

Chopra¹,

Chalifour²,

Schipper³

1995

Molecular Brain Research

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Multiple mRNA species generated by alternate polyadenylation from the rat manganese superoxide dismutase gene

Cited by 64 publications

References 28 publications

Tat protein of human immunodeficiency virus type 1 represses expression of manganese superoxide dismutase in HeLa cells.

Tat protein of human immunodeficiency virus type 1 represses expression of manganese superoxide dismutase in HeLa cells.

A Coding Region Determinant of Instability Regulates Levels of Manganese Superoxide Dismutase mRNA

Differential effects of cysteamine on heat shock protein induction and cytoplasmic granulation in astrocytes and glioma cells

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