Comparison of nucleotide sequences of the rplJL leader in Enterobacteria

The potential mRNA target sites for the ribosomal protein L10 found in Streptomyces griseus and S. coelicolor give evidence for the autogenous regulation of expression of the rplJL genes

“…In case of the rplJL operon, whose genes are regulated by r-protein LIO (or its 1 :4 complex with L12) [2] we observed the possibility for heterologous translational feedback control in Enterobacteria [3,4], provided by the highly conserved structure of both, the regulatory LIO proteins [5] and their mRNA target sites [6]. Of particular interest is the fact, that in case of the LIO target sites, whose structure is proved for Enterobacteria [6] and putative -for Synechocystis PCC 6803 [7] and Thermotoga ma ritima ([8]; Paton and Zhyvoloup, unpublished data), the degree of ho mology between the mRNA target sites is higher than between the res pective rRNA targets. Moreover, additional structural similarity between the m-and rRNA targets of the LIO protein is characteristic of Entero bacteria, Synechocystis and Thermotoga.…”

“…This makes it reasonable to as sume that the L10-RNA interaction, which mediates the autogenous re gulation of the rplJL genes expression is species-and organism-specific. Existence of the «specifying» complementary structural elements, is to be found in both, the regulatory proteins [9] and their mRNA binding sites [6][7][8]. The latter might be of importance to provide the efficient recognition and tight binding the LIO protein to the mRNA, which in the case of the rRNA target would be achieved via the cooperative binding of the neighbouring r-proteins.…”

“…The latter might be of importance to provide the efficient recognition and tight binding the LIO protein to the mRNA, which in the case of the rRNA target would be achieved via the cooperative binding of the neighbouring r-proteins. Comparison of the LIO binding regions in the rplJ leaders of seven enterobacterial species [6] reveals that the AA1571 -1572 (ennumeration as in E. coli [10,11]), whose interaction with the LIO protein had been proven by chemical analysis [11], are con-served. The conservation of AA1571-1572 in the potential LIO mRNA targets of Synechocystis and Thermotoga (see Fig.…”

“…The mRNA target site of the regulatory protein LIO is to be homo logous to the rRNA target in as much as to provide the competitive bin ding of the LIO protein. In all the cases documented so far [2,[6][7][8]11] the mRNA target sites for the LIO protein are located in the untranslated rpU leader region. In both species of Streptomyces, the untranslated lea der precedes the start of the LIO cistron.…”

“…Capitals denote nucleotides conserved amongst at least 30 of 31 aligned 23S RNA of eukaryotes, archaebacteria and eubacteria; R and Y -conservations as purines or pyrimidines. Base-pairs proven by coordinated base changes in all three kingdoms are denoted by lines; 2 -the secondary structure of the L10 binding domain of the S. ambofaciens 23S RNA [17]);£ -mRNA target sites of L10 (1 -the potential LIO target sites of S. griseus and 2 -S. coelicolor, lower case letters denote nucleotides conserved in both species; 3 -secondary structure of the potential L10 target site of Thermotoga maritima based on the nucleotide sequence [6] and mRNA secondary structure computation; 4the potential target of the Synechocysils PCC 6B03 [7]; 5 -secondary structure of the consensus enterobacterial mRNA target based on comoarison of the nucleotide sequences [2,4] and secondary structure prediction. Asterisks denote the variable nucleotides; 6 -secondary structure of the L10 mRNA target, consensus for Entervbacteria, Th.…”