Regulons are collections of coordinately regulated genes and operons that can be controlled by alternative sigma factors, such as sigma S. Some of the genes and operons expressed in response to sigma S are primary targets that are directly bound by sigma S. Others are indirect, secondary targets of sigma S and are activated by a primary target protein. You want to determine if gene X is a direct primary target of sigma S, or an indirect secondary target. To do so, you perform experiments with transcription and translation inhibitors and look for gene X RNA synthesis. Which experiment and result unambiguously points to gene X being a direct, primary target of sigma S