Biomedical subjects

P Reisdorf

Publications and source records attributed to P Reisdorf.

4 recordsLinked to original sources

PubMed1994

MBR1 and MBR3, two related yeast genes that can suppress the growth defect of hap2, hap3 and hap4 mutants.

Two new yeast genes, named MBR1 and MBR3, were isolated as multicopy suppressors of the growth defect of a strain lacking the HAP2 transcriptional activator. Both genes when overexpressed can also suppress the growth defect of hap3 and hap4 null mutants. However, overexpression of MBR1 cannot substitute for the HAP2/3/4 complex in activation of the CYC1 gene. Nucleotide sequencing of MBR1 and MBR3 revealed that these two genes encode serine-rich, hydrophilic proteins with regions of significant homology. The functional importance of one of these conserved regions was shown by mutagenesis. Disruption of MBR1 leads to a partial growth defect on glycerol medium. Disruption of MBR3 has no major effect but the double disruptant shows a synthetic phenotype suggesting that the MBR1 and MBR3 gene products participate in common function.

Amino Acid Sequence↗

PubMed1993

Enhanced in vivo monooxygenase activities of mammalian P450s in engineered yeast cells producing high levels of NADPH-P450 reductase and human cytochrome b5.

We have engineered yeast genomic DNA to construct a set of strains producing various relative amounts of yeast NADPH-P450 reductase (Yred) and human cytochrome b5 (Hb5). Expression of cDNAs encoding human P450 1A1, 1A2, 3A4, 19A and mouse P450 1A1 in the different oxido-reduction backgrounds thus constituted were achieved after strain transformation by plasmid-based P450-encoding expression cassettes. The results indicate that the level of Yred strongly affects all activities tested. In contrast, the amount of Hb5 affects activities in a manner that is dependent both on the P450 isoform considered and the Yred level. In a strain containing optimized amounts of Hb5 and Yred, human P450 3A4-specific testosterone-6 beta-hydroxylase activity can be enhanced as much as 73-fold in comparison with the activity observed in a wild-type strain. Bioconversion of sterols or xenobiotics was easily achieved in vivo using this new co-expression system.

Animals↗

PubMed1993

Epitope-tagging vectors designed for yeast.

In order to facilitate the process of epitope-tagging of yeast proteins, we have constructed two Saccharomyces cerevisiae-Escherichia coli shuttle vectors that allow fusion of a sequence encoding an epitope of the human c-myc protein at the 3' end of any gene. An example of the use of this technique is presented.

Amino Acid Sequence↗

PubMed1992

Individual differences in bridging inference processes.

The role of individual differences in bridging-inference processing was studied. Students (n = 135) read passages of short to moderate length. After each one, they answered corresponding questions about inferences that bridged causally related ideas that were either near or far apart in the text. The main hypothesis was that local bridging-inference processing is facilitated by the reader's predisposition to access pertinent knowledge during comprehension. Regression analyses provided support for this proposal and indicated that greater working-memory capacity and vocabulary knowledge promote inference processing. The following relationships between the predictors and inference processing were proposed: Knowledge access promotes the co-occurrence in working memory of the text ideas and knowledge needed to compute the bridge. Working-memory capacity enhances the likelihood that needed antecedent ideas will be available to the bridging processes. Vocabulary knowledge may promote inference processing because unfamiliar word meanings place more demands on working-memory resources than do familiar meanings.

Adult↗