The signal peptide sequence of a lytic transglycosylase of Neisseria meningitidis is involved in regulation of gene expression

Abstract

The 60 nucleotides encoding the signal peptide of the Neisseria meningitidis membrane-bound lytic transglycosylase (MltA) homologue GNA33 were found to exert a negative regulatory effect on expression of GNA33 from either a T7-or a P lac -driven system in Escherichia coli. Down-regulation was observed to occur at the transcriptional/post-transcriptional level and could possibly be ascribed to the formation of a stem-loop secondary structure within the signal peptide sequence. Slowing down the transcription rate through inhibition/titration of the RNA polymerase resulted in a considerable increase in mRNA accumulation, suggesting that a better coupling of translation to transcription would impede the formation of the putative secondary structure. Screening of synonymous mutations in the signal peptide sequence that showed high-level expression of an in-frame fusion to a reporter resulted in the isolation of several deletion mutants lacking most of the sequence participating in the putative secondary structure. Interestingly, the increase in the steady-state mRNA level observed in deletion mutants was higher, reaching a 300-fold increment, than that found in substitution mutants. Our results support the hypothesis that the rate of transcription controls the formation of a secondary structure in the region of the GNA33 transcript corresponding to the signal peptide sequence and this, when formed, negatively regulates expression.

The protease‐activated receptor 1 possesses a functional and cleavable signal peptide which is necessary for receptor expression

“…The prediction indicates that the sequence encoding the signal peptide of PAR1 forms a GC‐rich long stem loop which is absent in the case of ΔSP.PAR1. Formation of such stem loops has indeed been shown to stabilize mRNA structures consistent with the results above [18,19].…”

The Lytic Transglycosylases ofNeisseria gonorrhoeae

“…Upstream of gna33 is a stem-loop structure, and this structure reduced transcription of gna33. 52 Factors affecting transcription have not been identified, but it may be advantageous for Neisseria to produce LtgC only after the septum has been formed.…”

“…Control of LTs may occur partly by transcriptional and translational regulation as was observed for LtgC homologue GNA33 by Serruto. 52 Also, localization and binding to the degradation/synthesis complex may limit LT activity to its appropriate place and conditions.…”

Human signal peptide had advantage over mouse in secretory expression

“…It has been reported that properties of residues at the h/c boundary and +1 position of mature protein can inXuence the translocation and cleavage of signal peptide (Nothwehr et al 1990;Barkocy-Gallagher and Bassford 1992). Besides that, the signal peptide can also aVect the regulation of gene expression (Serruto and Galeotti 2004), and it has an eVect on the secretion of protein production (Holden et al 2005;Knappskog et al 2007). After that, we compared the eYciency of two signal sequence from human and mouse nerve growth factor.…”