Genes have been identified in the Methylomonas genome that are responsive to various metabolic and growth conditions. The identified responsiveness of these genes allows for the use of their promoters in regulated gene expression in C1 metabolizing bacteria. In particular, the hps promoter, which in its native state drives the expression of 3-hexulose-6-phosphate synthase (HPS), was found to be useful for directing expression of heterolgous coding regions (e.g., crtZ) in the obligate methanotroph Methylomonas sp. 16a.