AlpA is a transcriptional regulator of intA expression . It is part of the CP4-57 cryptic prophage that is similar to bacteriophage P4 .
alpA was first identified as a multicopy suppressor of lon mutants that leads to the expression of an alternative Lon protease activity named Alp [1, 3]. AlpA expression leads to increased synthesis of IntA, which results in excision of the CP4-57 cryptic prophage. The excision inactivates the gene upstream of intA, ssrA, encoding |FRAME: SSRA-RNA| .
Expression of alpA increases 6.5-fold upon deletion of tqsA; alpA expression may thus be involved in biofilm formation .
CP4-57: "cryptic P4-like prophage at min 57" 
AlpA: "alternative Lon protease" Read more >