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Biomedical subjects

J Abelson

Publications and source records attributed to J Abelson.

At least 163 records · Page 9Linked to original sources
PubMed1973

Transfer RNA synthesis in vitro.

During infection of Escherichia coli, bacteriophage T4 directs the synthesis of at least eight transfer RNAs and of two stable RNA species of low molecular weight, of unknown function. When T4 DNA is incubated with purified RNA polymerase and the appropriate substrates, a high molecular weight RNA is produced. This RNA, on further incubation with a supernatant fraction prepared from E. coli, is cleaved to several species of RNA. These cleaved RNAs were analyzed by gel electrophoresis and fingerprint techniques, and were found to be similar or identical to those made in vivo. The fingerprint analysis of one of these, a tRNA(Gly), is presented. The molecule made in vitro, except for the absence of modified bases, appears to be identical to the RNA made by T4-infected cells. Therefore, in this system the tRNA genes are transcribed with fidelity, the transcript is cleaved correctly, and the tRNAs are made in good yield.

Base Sequence↗
PubMed1973

Genetic mapping of the inversion loop in bacteriophage Mu DNA.

An inversion loop seen in heteroduplex mapping of the DNA of mature Mu phage induced from a lysogen is observed also in defective lambda phage carrying one end of Mu. 14% of the DNA of Mu, including this region, designated the G loop, is shown to be to the right of all known genes in the prophage map. The inhomogeneous ends of Mu are observed as a separate phenomenon and appear in all mutants investigated. The recA and recBC functions of the host are not needed for the inversion responsible for the G loop to take place. Deletions of Mu DNA in the G-loop region have been isolated and are under study.

Chromosome Mapping↗
PubMed1970

Mu-1 bacteriophage DNA.

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Centrifugation, Density Gradient↗
PubMedDate not supplied

Reliability and clinical validity of UM-CIDI DSM-III-R generalized anxiety disorder.

This is the first in a series of reports on the long-term test-retest reliability and procedural validity of the UM-CIDI, a modified version of the Composite International Diagnostic Interview used in the US National Comorbidity Survey (NCS). This report focuses on DSM-III-R Generalized Anxiety Disorder (GAD). The NCS administered the UM-CIDI to a nationally representative sample of 8098 respondents in the age range 15-54. A subsample of 36 respondents was subsequently selected for clinical reappraisal of GAD, consisting of reinterviewing by a clinical reappraisal interviewer who blindly readministered the GAD section of the UM-CIDI followed by an expanded version of the GAD section of the Structured Clinical Interview for DSM-III-R (SCID). The test-retest reliability of UM-CIDI/DSM-III-R lifetime GAD is Kappa = .53. When the requirement that the worries be excessive or unrealistic (A2) is removed, as in ICD-10 and partially in DSM-IV, reliability increases to Kappa = .78. The concordance between the baseline UM-CIDI diagnosis and the SCID diagnosis is Kappa = .35, while the cross-sectional concordance is Kappa = .47 (.66 when the Criterion A2 requirement is removed). Item-level analysis shows that lack of concordance between the UM-CIDI and the SCID is due largely to Criteria A2 and D. The A2 problem could be addressed either by deemphasizing the cognitive-evaluative component of GAD as in ICD-10, or by removing consideration of the term "unrealistic" from the criterion as in DSM-IV and more clearly specifying the meaning of the term "excessive". These options require further research on similarities and differences in risk factors, course, family history, and treatment response of more narrowly and broadly defined GAD. The Criterion D problem is due to lack of clarity in what constitutes a symptom occurring "often". This is clarified in DSM-IV. It is likely that this clarification will make it possible to develop more precisely structured questions to evaluate Criterion D in subsequent revisions of the UM-CIDI, resulting in improved reliability and validity.

Adolescent↗
PubMedDate not supplied

A test for intron function in the yeast actin gene.

Many eukaryotic genes contain intervening sequences (IVS), but the rationale for their existence remains a mystery. Previous studies done in our laboratory demonstrated that the intron in a yeast tRNATyr gene, SUP6, does have a function. We used the same approach to determine the role of introns in nuclear genes encoding messenger RNAs. A single actin gene with one intron exists in Saccharomyces cerevisiae. The level of actin in yeast appears to be crucial to viability: either too much or too little actin inhibits growth. Therefore, small effects on synthesis of actin protein resulting from the removal of the actin gene intron would be expected to cause measurable changes in cell growth. In the present study, an intron-deleted actin gene was constructed in vitro and was used to replace the single resident actin gene in a haploid strain. Analysis of the cells carrying the intron-deleted actin gene shows that the intervening sequence is not essential for actin gene expression.

Actins↗