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Record W1464760312 · doi:10.1128/9781555818180.ch12

Local Genetic Context, Supercoiling, and Gene Expression

2014· book-chapter· en· W1464760312 on OpenAlexaff
Andrew St. Jean

Bibliographic record

VenueASM Press eBooks · 2014
Typebook-chapter
Languageen
FieldBiochemistry, Genetics and Molecular Biology
TopicBacterial Genetics and Biotechnology
Canadian institutionsUniversity of Ottawa
Fundersnot available
KeywordsDNA supercoilPlasmidTranscription (linguistics)GeneBiologyDNAGeneticsRNA polymeraseGenomeGene expressionEscherichia coliDNA replication

Abstract

fetched live from OpenAlex

This chapter discusses the influence a gene's neighbors can have on that gene's expression and looks at the mechanisms by which this can occur. Both the packaging of DNA and its metabolic functioning are greatly facilitated by supercoiling. Supercoiling imparts torsional stress to DNA, which influences its interaction with RNA polymerase and other DNA-binding proteins as well as contributing to its compaction. The importance of supercoiling to cellular functioning is illustrated by the tight control prokaryotes maintain over this property of their genomes. The greatest difference between small plasmids and larger molecules may be that plasmids can rotate the entire molecule around its long axis during transcription, relieving local changes in supercoding levels. One additional finding that further supports the twin-supercoil domain model is that the length of the transcript located upstream from the leu-500 promoter affects the level of supercoiling changes. The large difference in transcription rates between mutant and wild-type strains may here be obscuring the fact that doubling the output of a gene can have significant consequences for a cell, either good or bad, depending on the situation. 4,5',8-trimethylpsoralen (TMP) is a sensitive indicator of supercoiling, and it is claimed to be able to detect changes in supercoil levels of 15% and 12%. Changes of this magnitude are regularly experienced by the genome of Escherichia coli.

Fetched live from OpenAlex and de-inverted. Abstracts are not stored in this database: the inverted indexes are 8.6 GB of the frame’s 9.3 GB of text, and the host has 13 GB free.

How this classification was reachedexpand

Full frame machine prediction

Teacher imitation

Not calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.

metaresearch head score (Codex)0.000
metaresearch head score (Gemma)0.000
Version: metacan-v3-hybrid-931329e0061cValidation status: machine_predicted_unvalidated
Candidate categoriesnone
Consensus categoriesnone
DomainCandidate signal: none · Consensus signal: none
Study designCandidate signal: Not applicable · Consensus signal: none
GenreCandidate signal: Review · Consensus signal: Review
Teacher disagreement score0.011
Threshold uncertainty score0.036

Distilled classifier scores by category (both heads)

CategoryCodexGemma
Metaresearch0.0000.000
Meta-epidemiology (narrow)0.0000.000
Meta-epidemiology (broad)0.0000.000
Bibliometrics0.0000.001
Science and technology studies0.0000.001
Scholarly communication0.0010.001
Open science0.0000.001
Research integrity0.0000.001
Insufficient payload (model declined to judge)0.0110.003

Machine scores (provisional)

The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.

Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.

Opus teacher head0.012
GPT teacher head0.209
Teacher spread0.197 · how far apart the two teachers sit on this one work
Validation statusscore_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from it

Classification

machine, unvalidated

Machine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.

The models applied no category: nothing in the taxonomy fit this work.
Study designNot applicable
Domainnot available
GenreReview

How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".

Quick stats

Citations1
Published2014
Admission routes1
Has abstractyes

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