Targeted Gene Deletion in Aspergillus fumigatus Using the Hygromycin-Resistance Split-Marker Approach
Bibliographic record
Abstract
The construction of a fungal strain that lacks a specific gene product is often accomplished by replacing the gene of interest with a selection marker using site-specific recombination. Transformation of Aspergillus fumigatus, like many related fungal species, must overcome two major obstacles. First, the cell wall limits the entry of exogenous DNA, and second, a high rate of nonhomologous recombination leads to random ectopic integration of the marker. Here, we describe an experimental strategy that has been successfully used to overcome these challenges through protoplast transformation with split-marker cassettes. Each cassette is constructed to contain sequences flanking the gene of interest fused to an incomplete fragment of a dominant selection marker. The resistance marker is only functional if both fragments undergo recombination to regenerate an intact resistance cassette. This event is favored by the proximity of the DNA constructs that arises as a result of homologous recombination between the target-gene sequences in the deletion construct with the fungal chromosome. A similar strategy can be employed using a second resistance marker to complement the deletion mutant with an intact allele of the gene of interest.
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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 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.001 |
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".