Ribosomal protein S1 promotes transcriptional cycling.
Prokaryotic RNA polymerases are capable of efficient, continuous synthesis of RNA in vivo, yet purified polymerase-DNA model systems for RNA synthesis typically produce only a limited number of catalytic turnovers. Here, we report that the ribosomal protein S1--which plays critical roles in translation initiation and elongation in Escherichia coli and is believed to stabilize mRNA on the ribosome--is a potent activator of transcriptional cycling in vitro. Deletion of the two C-terminal RNA-binding modules--out of a total of six loosely homologous RNA-binding modules present in S1--resulted in a near-loss of the ability of S1 to enhance transcription, whereas disruption of the very last C-terminal RNA-binding module had only a mild effect. We propose that, in vivo, cooperative interaction of multiple RNA-binding modules in S1 may enhance the transcript release from RNA polymerase, alleviating its inhibitory effect and enabling the core enzyme for continuous reinitiation of transcription.
Sukhodolets
Maxim V
MV
Department of Chemistry and Physics, Lamar University, Beaumont, Texas 77710, USA. soukhodomv@hal.lamar.edu
Garges
Susan
S
Adhya
Sankar
S
D000595:Amino Acid Sequence; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D020035:Holoenzymes / Q000302:isolation & purification / Q000378:metabolism; D066298:In Vitro Techniques; D008954:Models, Biological; D014176:Protein Biosynthesis; D012329:RNA, Bacterial / Q000235:genetics / Q000378:metabolism*; D012269:Ribosomal Proteins / Q000737:chemistry / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D012270:Ribosomes / Q000378:metabolism; D017384:Sequence Deletion / Q000235:genetics; D014158:Transcription, Genetic
D029968:Escherichia coli Proteins; D020035:Holoenzymes; D012329:RNA, Bacterial; D012269:Ribosomal Proteins; C015494:ribosomal protein S1; D012321:DNA-Directed RNA Polymerases