Functional importance of sequence in the stem-loop of a transcription terminator.
Intrinsic transcription terminators of prokaryotes are distinguished by a common RNA motif: a stem-loop structure high in guanine and cytosine content, followed by multiple uridine residues. Models explaining intrinsic terminators postulate that the stem-loop sequence is necessary only to form structure. In the tR2 terminator of coliphage lambda, single-nucleotide changes reducing potential RNA stem stability eliminated tR2 activity, and a compensatory change that restored the stem structure restored terminator activity. However, multiple changes in the stem sequence that should have either maintained or increased stability reduced terminator activity. These results suggest that the ability of the stem-loop structure to signal transcription termination depends on sequence specificity and secondary structure.
Cheng
S W
SW
Department of Microbiology and Immunology, University of Michigan Medical School, Ann Arbor 48109.
Lynch
E C
EC
Leason
K R
KR
Court
D L
DL
Shapiro
B A
BA
Friedman
D I
DI
D010582:Bacteriophage lambda / Q000235:genetics*; D001483:Base Sequence; D004252:DNA Mutational Analysis; D015967:Gene Expression Regulation, Viral; D005814:Genes, Viral; D008969:Molecular Sequence Data; D009690:Nucleic Acid Conformation; D012333:RNA, Messenger / Q000235:genetics; D012367:RNA, Viral / Q000235:genetics; D012045:Regulatory Sequences, Nucleic Acid; D015183:Restriction Mapping; D013728:Terminator Regions, Genetic; D014158:Transcription, Genetic; D015678:Viral Structural Proteins / Q000235:genetics
D012333:RNA, Messenger; D012367:RNA, Viral; D015678:Viral Structural Proteins