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L A Moran

Publications and source records attributed to L A Moran.

23 records · Page 2Linked to original sources
PubMed1984

Expression of a Drosophila heat-shock gene in cells of the yeast Saccharomyces cerevisiae.

A 3.52-kilobase (kb) segment of Drosophila melanogaster DNA carrying the 2.15-kb transcribed sequence for the 70 000-dalton heat-shock protein (hsp70) and 1.14-kb of the 5' flanking sequence was inserted into an autonomously replicating chimeric plasmid and used to transform the yeast Saccharomyces cerevisiae. The Drosophila gene is efficiently transcribed in the transformed cells, yielding a transcript which is 21 nucleotides shorter than the normal Drosophila mRNA at the 5' end. Significant increases in the amount of Drosophila-specific RNA occur when the transformed cells are subjected to heat shock, indicating that the Drosophila gene is inducible in the yeast cells.

Animals↗
PubMed1984

Proteins related to the mouse L-cell major heat shock protein are synthesized in the absence of heat shock gene expression.

Heat shock of mouse L cells induces the synthesis of two polypeptides of Mrs 68,000 and 89,000. Using a fragment of a cloned gene encoding the Drosophila melanogaster Mr 70,000 heat shock protein (hsp70), we have shown that this protein has been highly conserved during eukaryotic evolution. We extended this observation by probing at low stringency for the expression in mouse L cells of RNA homologous to the Drosophila hsp70 gene. In addition to the RNA encoding the inducible Mr 68,000 heat shock protein (hsp68), there are mouse mRNAs encoding proteins of Mrs 70,000 and 74,000 that are homologous to the Drosophila hsp70 gene. The Mrs 70,000 and 74,000 proteins and their mRNAs are abundant components of unstressed mouse L cells. These constituitively expressed proteins are unique polypeptides in contrast to the several isoelectric point variants of the inducible hsp68. We do not detect hsp68 or its mRNA in unstressed L cells. In addition to the mRNAs corresponding to hsp68 and the Mrs 74,000 and 70,000 proteins, we detect a fourth RNA homologous to the Drosophila hsp70 gene but whose protein product has not been identified. Our results suggest that the hsp68 gene of mouse L cells is a member of a multigene family and that the individual family members are distinguishable by their degree of similarity but show differences in the regulation of their expression.

Animals↗
PubMed1983

The major heat-shock protein (hsp70) gene family: related sequences in mouse, Drosophila, and yeast.

Heat shock induces the synthesis of a 70-kdalton protein in Escherichia coli, Drosophila, yeast, and mouse. We show that the genes for this heat-shock protein in mouse, yeast, and Drosophila share extensive sequence homology as determined by heteroduplex formation at different stringencies. We calculate that the heat-shock gene homology is 74% between yeast and Drosophila and 85% between mouse and Drosophila. The organization of the six copies of the Drosophila gene for the 70-kdalton heat-shock protein at two separate loci is summarized and evidence is presented that the yeast and mouse genomes each contain multiple copies of sequences related to the Drosophila gene for the 70-kdalton heat-shock protein. These results demonstrate that not only the sequence but also the repetitive organization of the major heat-shock genes is conserved.

Animals↗
PubMed1979

Purification of gene 41 protein of bacteriophage T4.

The T4 bacteriophage gene 41 protein is known from genetic analysis to be essential for phage DNA replication in vivo. It became possible to monitor the activity of this protein during purification after development of an "in vitro complementation assay," which measures its stimulation of DNA synthesis in a concentrated crude lysate prepared from Escherichia coli cells infected with a T4 bacteriophage mutant in gene 41 (L. Moran and B. Alberts, manuscript in preparation). In this report, a purification procedure involving three chromatographic steps is described which reproducibly yields a 90% homogeneous preparation of this rather unstable protein. The major polypeptide chain present (58,000 daltons) is shown to cosediment with a DNA-dependent GTPase (and ATPase) activity, and to induce extensive in vitro DNA synthesis on both single- and double-stranded DNA templates when incubated with our preparations of five other purified T4 DNA replication proteins (plus deoxyribonucleoside and ribonucleoside triphosphates).

Coliphages↗