tetAA

tetAA is not a widely standardized gene symbol in public genomic databases. In many cases, the term may represent a misannotation, a typographical variant of tetA, or a designation for a tandem arrangement of two tetA-like units in a particular plasmid or genome. The tetracycline resistance gene family more commonly uses names such as tetA, tetB, tetC, tetD, tetG, tetM, and tetO, among others.

When tetA is present in bacteria, it typically encodes a membrane-associated efflux pump that exports tetracycline out of the cell, reducing intracellular drug concentration and conferring resistance. The expression of tetA is often regulated by a TetR-like repressor, which binds to a corresponding operator and inhibits transcription in the absence of tetracycline. In many plasmid-borne systems, tetA is linked to tetR and to regulatory sequences that enable inducible expression in response to tetracycline exposure.

If tetAA appears in a sequence annotation, it should be interpreted with caution. Researchers are advised to check the specific organism, plasmid, or annotation source to determine whether tetAA represents a duplication, a variant, or a potential misannotation of a known tet gene. Cross-referencing with curated databases and, if possible, examining the surrounding genetic context (promoters, regulators, and neighboring resistance genes) can help clarify its meaning.

See also: tetracycline resistance, tet gene family, TetR regulation.