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M Hirsch-Kauffmann

Publications and source records attributed to M Hirsch-Kauffmann.

65 records · Page 4Linked to original sources
PubMed1975

Transcriptional units for ribosomal proteins of Escherichia coli.

Transcriptional units for ribosomal proteins in Escherichia coli were measured using the ultraviolet sensitivities of the rates of synthesis of individual ribosomal proteins. The ultraviolet sensitivities of gene transcriptions are proportional to the distances from the promoters. The longest transcriptional units for ribosomal proteins are 3.6 x 10(6) of DNA molecular weight corresponding to 1.8 x 10(6) of RNA or to 180 000 of protein. The length would cover 10--12 genes of ribosomal proteins (of an average Mr of 15000-18000).

Bacterial Proteins↗
PubMed1975

In vivo and in vitro phosphorylation of DNA-dependent RNA polymerase of Escherichia coli by bacteriophage-T7-induced protein kinase.

After infection with bacteriophage T7 the beta' and to a lesser extent the beta subunits of E. coli DNA-dependent RNA polymerase (nucleosidetriphosphate:RNA nucleotidyltransferase, EC 2.7.7.6) are phosphorylated by a phage-gene-encoded protein kinase (ATP:protein phosphotransferase, EC 2.7.1.37). The phosphorylation occurs on threonine residues and appears site-specific. It is probably the molecular basis of the early transcriptional control.

Coliphages↗
PubMed1972

Intracellular forms of adenovirus deoxyribonucleic acid. I. Evidence for a deoxyribonucleic acid-protein complex in baby hamster kidney cells infected with adenovirus type 12.

The total intracellular deoxyribonucleic acid (DNA) from baby hamster kidney cells abortively infected with (3)H-adenovirus type 12 was analyzed in dye-buoyant density gradients. Between 10 and 20% of the cell-associated radioactivity derived from viral DNA bands in a density position which is 0.043 to 0.085 g/cm(3) higher than that of viral DNA extracted from purified virions. The DNA in the high-density region (HP-fraction) is almost completely absent when DNA, ribonucleic acid (RNA) or protein synthesis is chemically inhibited in separate experiments. The HP-fraction is not found when the virus does not adsorb to and enter the cell. The DNA in the HP-fraction appears as early as 2 hr after inoculation. At 2 hr after infection, the HP-fraction is present both in the nucleus and the cytoplasm. This DNA hybridizes exclusively with viral DNA and sediments at approximately the same rate in both neutral and alkaline sucrose density gradients. Electron microscopy has revealed no circular DNA molecules in this fraction. Evidence indicates that the viral DNA in the HP-fraction exists in a complex with protein and possibly RNA. The protein component of the complex is resistant to enzymatic digestion, whereas the complex is susceptible to ribonuclease treatment. Digestion with deoxyribonuclease reduces the amount of DNA found in the HP-fraction. The structure and biological function of this complex are currently being investigated.

Adenoviridae↗
PubMed1969

Control of gene function in bacteriophage T4. I. Ribonucleic acid and deoxyribonucleic acid metabolism in T4rII-infected lambda-lysogenic hosts.

Deoxyribonucleic acid (DNA) synthesis in T4rII-infected, lambda-lysogenic strains of Escherichia coli proceeds with one-half the rate of T4 wild-infected bacteria and stops 16 min after infection at 37 C. The rates of ribonucleic acid (RNA) synthesis, however, are the same with T4rII and T4 wild. The turnover of pulse-labeled RNA is slow in K strains (half-lives 10 to 20 min) as compared with B strains (half-lives 2.5 to 6 min). Lambda-lysogeny increases the apparent messenger (m) RNA half-lives in pulse-chase experiments. The shutoff of host RNA synthesis in T4rII infected K(lambda) is incomplete. Moreover, the preferential transcription of T4 DNA ceases 13 min after infection, and transcription of host and prophage lambda DNA is resumed. The T4 RNA synthesized in rII-infected K(lambda) contains no late T4 mRNA. The early portion of the T4 genome, however, is transcribed completely. The T4-induced early modification of bacterial RNA polymerase does occur. Resumption of host DNA transcription at 13 min after infection is not associated with a reversal of the above polymerase modification. It is concluded that in lambdalysogenic bacteria T4rII infections are abortive because RNA polymerase is prevented from transcribing late T4 genes.

Centrifugation, Density Gradient↗
PubMedDate not supplied

Werner syndrome: characterization of mutations in the WRN gene in an affected family.

Affected and unaffected members of a Caucasian family with Werner syndrome were analyzed for mutations in the recently described Werner syndrome (WRN) gene and for their relevance to phenotypic expression of chromosomal instability and x-ray hypersensitivity. Two distinct molecular alterations were documented in the family. Analysis of the genomic DNA revealed a single-base exchange from A to T at an intron-exon boundary in the otherwise strongly conserved 5' donor splice site. Consequently, exon 30 is spliced together with the intron. The ensuing structure could be confirmed by the presence and calculated size of the resulting RNA fragments. The patients, all compound heterozygotes, had a 1-bp deletion in the first third of the coding sequence in the other allele. The genotypes of the family members for these mutations were determined and consequences for the cellular phenotype of the otherwise unaffected heterozygotes are documented.

Adult↗