Study On The SRNA Coding Gene YigP In Escherichia Coli

YigP gene exists in many species, and the sequence is conserved among bacteria. In Escherichia coli, yigP gene(GeneID:948915) locates between ubiquinone biosynthetic genes ubiE and ubiB. GeneBank annotates yigP as a putative protein-coding gene, however, no research focusing on the yigP gene has been reported yet.Our previous work have confirmed that the strain with yigP inactivation in chromosome must rely on a complementary plasmid containing a wild-type yigP gene, to survive under laboratory growth conditions. Promoter activity was detected in the region of upstream yigP-Using RACE techniques, we confirmed that yigP gene was transcribed to a 252 nt RNA molecule.In this study, we have shown that a 297bp fragment downstream of yigP was enough to complement the chromosomal defective yigP gene. Using lacZ as a report gene, we have identified the precise region of yigP promoter. Meanwhile, the -10 and -35 region of yigP promoter were identified by site mutations and a negative transcriptional regulatory region was also discovered associating with promoter activity. Notably, the yigP gene is immune to frameshift mutations. This indicates yigP is a non-coding RNA gene, rather than a protein coding gene as predicted in the GeneBank. What's more, our reverse transiption PCR have showed that yigP could cotranscribed with its neighbouring genes ubiE and ubiB.In conclusion, our studies revealed that yigP is an essential non-coding RNA gene.