Figure 1.
ArgP-mediated regulation by Arg, Lys, and CAN of argO transcription. (A) Sequence of the argO regulatory region used in this study, numbered with respect to the A residue (in bold) representing the start site of transcription (taken as +1). Promoter −35 and −10 motifs and GTG triplet representing start site of translation have lines above them. Inverted-repeat sequence is marked by overhead arrows. The ArgP region from around −85 to −20 (as determined in this study) is underlined and bracketed. The two −10-like motifs in the ITS are italicized. (B) In vivo argO-lac expression, measured as β-galactosidase-specific activities (sp act), in host strain derivatives with plasmid constructs carrying the argO regulatory region, either wild-type (wt) or with different mutations as described in the text. The host strain for top panel data was argP+ (except for bar at extreme left, which was from host with argP-null mutation) and that for bottom panel data was argPd-S94L. (C) Radiolabeled in vitro transcription products obtained with the 427-bp argO template (with sequence from −293 to +109), in reaction mixes with various additives as indicated, and subjected to electrophoresis on denaturing 10% polyacrylamide gel. (RO) Run-off transcript from argO promoter; (EE) end-to-end transcription product; (His) histidine.