A pathway‐specific transcriptional regulatory gene for nikkomycin biosynthesis in <i>Streptomyces ansochromogenes</i> that also influences colony development
Bibliographic record
Abstract
DNA sequence analysis of a 7.5 kb XhoI DNA fragment from the region flanking the nikkomycin biosynthesis gene cluster in Streptomyces ansochromogenes revealed one 3.3 kb open reading frame (ORF), designated sanG. The deduced product of sanG (1061 amino acids), which is similar to PimR of Streptomyces natalensis, contains an OmpR-like DNA binding domain in its N-terminal portion and A- and B-type nucleotide binding motifs in the middle of the protein. Disruption of sanG abolished nikkomycin biosynthesis, reduced sporulation and led to brown pigment accumulation. All aspects of this complex phenotype were complemented by a single copy sanG which was integrated into the chromosome. The introduction of multiple copies of sanG resulted in increased nikkomycin production. S1 mapping results indicated that sanG is transcribed from at least three promoters (P1, P2 and P3), P1 being strongly upregulated when production of nikkomycins starts. Two putative transcription units for nikkomycin biosynthesis, starting from sanN and sanO, are dependent on the expression of sanG, whereas a putative transcription unit starting from sanF was not regulated by sanG. These results suggested that sanG encodes a transcriptional activator important for nikkomycin biosynthesis that, unusually, also has pleiotropic effects on secondary metabolism and development.
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 imitationNot 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.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.000 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
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.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
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".