FIG. 2.

Expression of hoxA and hyp genes. Translational fusions for hoxA and hypB1 were generated by inserting restriction fragments into vector plasmid pPHU234. The resulting recombinants were mobilized into A. eutrophus H16, and reporter gene activity was monitored under hydrogenase-repressing (SN medium) and -derepressing (FGN medium and lithoautotrophic cultures) conditions. The relevant segment of each plasmid is shown schematically at the left; the corresponding β-galactosidase activities are shown at the right. The solid arrows denote the lacZ gene of the vector (not to scale). Bars represent the inserted A. eutrophus sequences. The shaded segment indicates the 5′ part of hoxA. Some of the genes are labeled for clarity (see Fig. 1). The restriction enzymes used to generate the insert are given below the bar. Bst, BstEII; E, EcoRI; H, HpaI; M, MroI; P, PvuII. pPHU278 is a control plasmid containing a Φ(aph-lacZ) fusion deleted for the aph promoter (20). Values are means of five independent measurements ± standard errors.