Structure of a genome region of the XXXX temperate phage phiadh covering a repressor gene and cognate promoters.

@entity10753 @entity24046 @entity70663 @entity7878 @entity3881
By sequencing the DNA regions which flank the intG gene encoding integrase of the temperate @entity24046 (Lb.) gasseri @entity70663 , a continuous sequence of 6590 bp was established. It encompasses five newly identified ORFs, of which four are located upstream, and one (orfC) downstream of intG. Proteins corresponding to the expected products of the intG upstream coding regions, orfA (33 kDa), orf2 (14 kDa), rad (12.1 kDa), and tec (7.9 kDa), were identified by in vitro expression of subcloned DNA fragments. Rad shares homology with transcription regulators, including SinR of Bacillus species and the repressor of @entity10753 . The gporf2 is similar to predicted products of topologically equivalent coding regions of the @entity7878 phage TP901-1 and the @entity3881 phage @entity10753 . Promoters for the divergently oriented rad and tec genes were mapped within the 435-bp region between them and specify overlapping transcripts with extended 5'-untranslated sequences. As shown with lacZ fusions, Rad repressed transcription from the tec and rad promoters 20- and 5-fold, respectively. In Lb. gasseri, weak expression of cloned rad ws sufficient to mediate immunity towards phiadh.
