knockout
The inactivation of a gene through deliberate disruption of its sequence, commonly achieved in CRISPR workflows via NHEJ-induced indels. Written as one word in biotechnology contexts.
Full Definition
In CRISPR genomics, a knockout refers to a cell line, organism, or allele in which a specific gene has been functionally inactivated—most often through NHEJ-induced frameshift indels that disrupt the reading frame and trigger nonsense-mediated decay. Editors should write it as one word ('knockout'), not hyphenated ('knock-out') or spaced ('knock out'), in noun and attributive-modifier uses. As a verb phrase, 'knock out' is two words. Knockout should not be used synonymously with knockdown, which refers to reduced (not abolished) gene expression.
Usage
Usage note: One word as noun/modifier: 'knockout'. Two words as verb: 'to knock out'. Never hyphenated as a noun or modifier. Distinguish from 'knockdown' (partial reduction) and 'knockin' (insertion of a sequence).
In Context
- "A CRISPR knockout cell line was generated by transfecting Cas9 and a gRNA targeting exon 2." — Methods section
- "The author had written 'knock-out' throughout; corrected to 'knockout' per journal style." — Proofreading note