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T A Rouault

Publications and source records attributed to T A Rouault.

61 records · Page 4Linked to original sources
PubMed1988

Deletional analysis of the promoter region of the human transferrin receptor gene.

Fragments of human genomic DNA corresponding to the promoter region of the gene for the transferrin receptor have been cloned upstream of the bacterial gene for chloramphenicol acetyltransferase and these constructs used to assess promoter activity following transfection into a human rhabdomyosarcoma cell line. Progressive 5' deletions as well as internal linker-substitution constructs support a critical role in gene expression of a sequence element approximately 70 bp upstream of the mRNA start site. In this region, the receptor gene was found to contain 11bp that are identical to a segment of the enhancers of polyoma virus and adenovirus. A fragment encompassing this element was shown to increase gene expression when the fragment was placed in either orientation upstream of the remainder of the transferrin receptor promoter but the same fragment did not activate an enhancer-less SV40 promoter. Removal from within the receptor promoter of three potential binding sites for the transcription factor Sp1 did not decrease the promoter's activity.

Acetyltransferases↗
PubMed1988

The promoter region of the human transferrin receptor gene.

Genomic DNA fragments corresponding to the promoter region of the human transferrin receptor were linked to either the full-length receptor cDNA or to the bacterial enzyme chloramphenicol acetyltransferase. These constructs were transfected into mouse and human cells, respectively. Gene expression was monitored 40-48 hours after transfection. Bal31 exonuclease was employed to produce 5' to 3' deletions of the promoter region. Deletion of DNA between -86 and -70 upstream of the receptor's mRNA start site resulted in a greater than 80% reduction in apparent promoter activity. DNA sequencing of the 150 bp upstream of the start site revealed that the promoter region contained several sequence elements more than 90% homologous to the consensus sequence for binding of the transcription factor Sp1. In addition, an 11 bp sequence identical to a segment of the enhancers of polyoma virus and adenovirus was located between -80 and -70. Internal deletions confirmed that this enhancer homologue was critical for full promoter activity. A 66 bp fragment encompassing the -80/-70 element augmented gene expression when the fragment was placed in either orientation upstream of the remainder of the transferrin receptor promoter.

Animals↗
PubMed1987

Identification of the iron-responsive element for the translational regulation of human ferritin mRNA.

Regulated translation of messenger RNA offers an important mechanism for the control of gene expression. The biosynthesis of the intracellular iron storage protein ferritin is translationally regulated by iron. A cis-acting element that is both necessary and sufficient for this translational regulation is present within the 5' nontranslated leader region of the human ferritin H-chain messenger RNA. In this report the iron-responsive element (IRE) was identified by deletional analysis. Moreover, a synthetic oligodeoxynucleotide was shown to be able to transfer iron regulation to a construct that would otherwise not be able to respond to iron. The IRE has been highly conserved and predates the evolutionary segregation between amphibians, birds, and man. The IRE may prove to be useful for the design of translationally regulated expression systems.

Base Sequence↗
PubMed1987

Influence of altered transcription on the translational control of human ferritin expression.

In this paper, we examine the response of a translational regulatory mechanism when changes in mRNA levels are induced. The gene that encodes the human ferritin heavy chain has been transfected into mouse fibroblasts. Stable transformants that express the human ferritin heavy chain have been isolated. This protein assembles into ferritin polymers and can co-assemble with host mouse ferritin. Biosynthetic rates of the expressed human ferritin varied over a wide range in response to perturbations in iron supply, but total and cytoplasmic messenger RNA levels remained unchanged. When changes in ferritin mRNA levels were induced by treatment with sodium butyrate, proportional changes in the biosynthetic rates of ferritin were observed, but the capacity for modulating biosynthesis in response to alterations in iron availability was preserved. These findings suggest that the final protein biosynthetic rate of a translationally regulated gene depends on both translational regulatory signals and underlying transcription rates.

Butyrates↗
PubMed1987

A cis-acting element is necessary and sufficient for translational regulation of human ferritin expression in response to iron.

Ferritin plays a key role in determining the intracellular fate of iron and is highly regulated by the iron status of the cell. We have identified a cis-acting element in the transcribed but nontranslated 5' leader sequence of human ferritin heavy-chain mRNA. In transiently transfected murine fibroblasts, the presence of a 157-nucleotide region of the 5' leader sequence was found to be necessary for iron-dependent regulation of ferritin biosynthesis. Further, this 5' leader region is sufficient to transfer iron-mediated translational control to the expression of a heterologous gene product, chloramphenicol acetyltransferase.

Base Sequence↗
PubMed1978

Differences in the terminal steps of complement lysis of normal and paroxysmal nocturnal hemoglobinuria red cells.

The number of microscopically visible lesions produced on the membrane for a given degree of lysis on normal cells as on PNH cells. Since complement lesions were not formed until C8 or C9 was incorporated into the complement sequence, the results suggest that increased lysis of red cells in PNH is due at least in part to more efficient penetration of the PNH membrane by the terminal lytic sequence of complement. Furthermore, the efficiency of the terminal lytic sequence in the lysis of PNH cells when complement was activated by the alternative pathway and the classical pathway was analyzed. There was no significant difference (p less than 0.01) in the number of lesion present at an equivalent degree of lysis when initiated by antibody, cobra venom factor, or acidification. Thus, the efficiency of the terminal lytic sequence does not vary with different modes of activation.

Complement C8↗