Escherichia coli SspA is a transcription activator for bacteriophage P1 late genes

摘要: Summary The stringent starvation protein A (SspA), an Escherichia coli RNA polymerase (RNAP)-associated protein, has been reported to be essential for lytic growth of bacteriophage P1. Unlike P1 early promoters, late promoters are not recognized by RNAP alone. phage-encoded Lpa (late promoter activator formerly called gp10), shown required transcription in vivo. Here, we demonstrate that SspA is a genes. Our results indicated limiting sspA mutant. However, the genes was deficient mutant We demonstrated SspA/Lpa activation Ps vitro. In addition, and were facilitate binding DNA. Activation dependent on holoenzyme containing σ70 but σS, indicating two activators discriminate between forms holoenzyme. Furthermore, gene expression downregulated wild-type background, whereas it persisted mediate transcriptional switch from during growth. Thus, this work provides first evidence function E. RNAP-associated SspA.