passages.id: split_8_test_3553_passage
passages.type: progene_text
passages.text: Three newly identified sigma X - dependent promoters precede genes encoding regulatory proteins : an AbrB homolog ( Abh ) , a putative response regulator aspartate phosphatase ( RapD ) , and a regulator of autolysin expression ( LytR ) . sigma X also contributes to the expression of CsbB , a putative membrane - bound glucosyl transferase that is partially controlled by the sigma B stress response sigma factor .