Molecular mimicry in translational regulation: the case of ribosomal protein S15.
Ribosomal protein S15 is highly conserved among prokaryotes. It plays a pivotal role in the assembly of the central domain of the small ribosomal subunit and regulates its own expression by a feedback mechanism at the translational level. The protein recognizes two RNA targets (rRNA and mRNA) that share only partial similarity. Its interaction with 16S rRNA has been fully characterized, while mRNA interactions and regulatory mechanisms have been extensively studied in E. coli and in T. thermophilus. Recently, we have characterized which aminoacids are involved in E. coli mRNA recognition, using an in vivo assay allowing to identify S15 mutations affecting the S15-mRNA interactions without altering 30S subunit assembly. Here, we address the following questions: Are common determinants used by S15 to recognize its rRNA and mRNA targets? What is the extent of molecular mimicry? Is the regulatory mechanism conserved? Our results indicate that specific recognition of mRNA and rRNA relies on both mimicry and site differentiation. They also highlight the high plasticity of RNA to adapt to evolutionary constraints.
Ehresmann
Chantal
C
UPR 9002 du CNRS, Institut de Biologie Moléculaire et Cellulaire, Strasbourg-Cedex, France. Chantal.Ehresmann@ibmc.u-strasbg.fr
Ehresmann
Bernard
B
Ennifar
Eric
E
Dumas
Philippe
P
Garber
Maria
M
Mathy
Nathalie
N
Nikulin
Alexei
A
Portier
Claude
C
Patel
Dinshaw
D
Serganov
Alexander
A
D001483:Base Sequence; D004926:Escherichia coli / Q000378:metabolism; D019143:Evolution, Molecular; D008957:Models, Genetic; D008958:Models, Molecular; D018716:Molecular Mimicry; D008969:Molecular Sequence Data; D009154:Mutation; D009690:Nucleic Acid Conformation; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000737:chemistry; D012335:RNA, Ribosomal / Q000737:chemistry; D012269:Ribosomal Proteins / Q000737:chemistry / Q000502:physiology*; D012270:Ribosomes / Q000737:chemistry; D016963:Thermus thermophilus / Q000378:metabolism
D012333:RNA, Messenger; D012335:RNA, Ribosomal; D012269:Ribosomal Proteins; C036004:ribosomal protein S15