Att site See attachment site. The gene product that controls its own expression. See autogenous repressor. Autogenous repressor The product of a regulator gene which binds to its own operator and prevents transcription of the associated structural genes. The emissions from the radioactive label expose the photographic film.
Autoregulation See autogenous regulation.
Autotroph An organism which does not require any organic carbon for its energy source or for its growth. A nutritional supplement required for growth of an auxotrophic strain. Avidin A protein that binds biotin with a very high affinity. Used for the detection of biotinylated probes.