This family consists of several phage antitermination protein Q and related bacterial sequences. Antiterminator proteins control gene expression by recognising control signals near the promoter and preventing transcriptional termination which would otherwise occur at sites that may be a long way downstream [1].

1: Transcriptional antitermination. Greenblatt J, Nodwell JR, Mason SW; Nature 1993;364:401-406. PMID:8332211

2: Arrangement and functional identification of genes in the regulatory region of lambdoid phage H-19B, a carrier of a Shiga-like toxin. Neely MN, Friedman DI; Gene 1998;223:105-113. PMID:9858702