Difference between revisions of "Part:BBa K581000"

Latest revision as of 19:41, 5 October 2011

sgrS1+Terminator (small RNA regulator, conjugate part of ptsG1)

SgrS1 is the G178C mutant of SgrS(wt) and the conjugate part of ptsG1 in our comparator device.

SgrS(sugar transport-related sRNA)(wt)[1] is a small RNA regulator that help cells recover from glucose-phosphate stress by base pairing with ptsG(wt) mRNA. SgrS regulates ptsG mRNA by short, imperfect base-pairing interactions; as a result, the expression of PtsG is repressed.

Teppei Morita et.al’ s work suggests that two mutations (C85G and C87G) in ptsG mRNA could completely impair the ability of SgrS to downregulate its expression, while compensatory mutations of SgrS (G178C and G176C) restore the gene silencing ability. These results indicate that it is the base pairing of the two RNAs rather than particular nucleotides that is important for SgrS action. They have also illustrated that sequence outside this region, even though complementary, is rather dispensable for the efficient silencing (Kawamoto et al., 2006). This makes mutant ptsG/SgrS pairs orthogonal to genetic context of the host cell. Therefore we choose this couple of conjugate mRNA/sRNA as the foundation of our comparator device design.

In our design， we developed the modular comparator that could respond to different signal molecules respectively. Two sets of mutant SgrS as well as its complementary ptsG mRNA were obtained simply by modifying ptsG(wt)/SgrS(wt). In detail, SgrS1 refers to the G178C(see Fig.1) mutants of SgrS(wt) which could help restore its complementarity to ptsG1[2].

                  
                 Fig.1 Sequence alignment of wildtype ptsG/SgrS pair mutant complementary pairs.         
                 The complementary pair of ptsG1 mRNA and corresponding SgrS1.

Sequence and Features