tRNA regulation of gene expression: interactions of an mRNA 5'-UTR with a regulatory tRNA.
Many genes encoding aminoacyl-tRNA synthetases and other amino acid-related products in Gram-positive bacteria, including important pathogens, are regulated through interaction of unacylated tRNA with the 5'-untranslated region (5'-UTR) of the mRNA. Each gene regulated by this mechanism responds specifically to the cognate tRNA, and specificity is determined by pairing of the anticodon of the tRNA with a codon sequence in the "Specifier Loop" of the 5'-UTR. For the 5'-UTR to function in gene regulation, the mRNA folding interactions must be sufficiently stable to present the codon sequence for productive binding to the anticodon of the matching tRNA. A model bimolecular system was developed in which the interaction between two half molecules ("Common" and "Specifier") would reconstitute the Specifier Loop region of the 5'-UTR of the Bacillus subtilis glyQS gene, encoding GlyRS mRNA. Gel mobility shift analysis and fluorescence spectroscopy yielded experimental Kds of 27.6 +/- 1.0 microM and 10.5 +/- 0.7 microM, respectively, for complex formation between Common and Specifier half molecules. The reconstituted 5'-UTR of the glyQS mRNA bound the anticodon stem and loop of tRNA(Gly) (ASL(Gly)(GCC)) specifically and with a significant affinity (Kd = 20.2 +/- 1.4 microM). Thus, the bimolecular 5'-UTR and ASL(Gly)(GCC) models mimic the RNA-RNA interaction required for T box gene regulation in vivo.
Nelson
Audrey R
AR
Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, North Carolina 27695-7622, USA.
Henkin
Tina M
TM
Agris
Paul F
PF
D020121:5' Untranslated Regions / Q000235:genetics*; D001412:Bacillus subtilis / Q000235:genetics; D001483:Base Sequence; D004591:Electrophoresis, Polyacrylamide Gel; D005786:Gene Expression Regulation; D008958:Models, Molecular; D009690:Nucleic Acid Conformation; D012329:RNA, Bacterial / Q000737:chemistry / Q000235:genetics; D012333:RNA, Messenger / Q000737:chemistry / Q000235:genetics*; D012343:RNA, Transfer / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism; D013050:Spectrometry, Fluorescence
D020121:5' Untranslated Regions; D012329:RNA, Bacterial; D012333:RNA, Messenger; D012343:RNA, Transfer