TY - JOUR
T1 - Genetic analysis of bacteriophage lambda cIII gene
T2 - mRNA structural requirements for translation initiation.
AU - Kornitzer, D.
AU - Teff, D.
AU - Altuvia, S.
AU - Oppenheim, A. B.
PY - 1989/5
Y1 - 1989/5
N2 - The bacteriophage lambda cIII gene product regulates the lysogenic pathway. The cIII gene is located in the leftward operon, which is transcribed from the pL promoter. We have previously shown (S. Altuvia and A. B. Oppenheim, J. Bacteriol. 167:415-419, 1986) that mutations that show elevated expression lie within the cIII coding sequence. We isolated mutants that show decreased CIII activity. All the mutations were found to cause a drastic reduction in the rate of initiation of cIII translation. Several mutations were found to be scattered within the first 40 nucleotides of the cIII coding region. Additional mutations affected the AUG initiation codon, the Shine-Dalgarno sequence, and the upstream RNaseIII processing site. Computer folding of the cIII mRNA suggested the presence of two alternative RNA structures. All the mutations within the coding region that reduce expression reduce the stability of one specific mRNA structure (structure B). Mutations that increase expression lie in the loops of this structure and may in fact stabilize it by interfering with the formation of the alternative structure (structure A). Thus, it appears that a specific mRNA secondary structure at the beginning of the cIII coding region is essential for efficient translation, suggesting that changes in mRNA structure regulate cIII expression.
AB - The bacteriophage lambda cIII gene product regulates the lysogenic pathway. The cIII gene is located in the leftward operon, which is transcribed from the pL promoter. We have previously shown (S. Altuvia and A. B. Oppenheim, J. Bacteriol. 167:415-419, 1986) that mutations that show elevated expression lie within the cIII coding sequence. We isolated mutants that show decreased CIII activity. All the mutations were found to cause a drastic reduction in the rate of initiation of cIII translation. Several mutations were found to be scattered within the first 40 nucleotides of the cIII coding region. Additional mutations affected the AUG initiation codon, the Shine-Dalgarno sequence, and the upstream RNaseIII processing site. Computer folding of the cIII mRNA suggested the presence of two alternative RNA structures. All the mutations within the coding region that reduce expression reduce the stability of one specific mRNA structure (structure B). Mutations that increase expression lie in the loops of this structure and may in fact stabilize it by interfering with the formation of the alternative structure (structure A). Thus, it appears that a specific mRNA secondary structure at the beginning of the cIII coding region is essential for efficient translation, suggesting that changes in mRNA structure regulate cIII expression.
UR - http://www.scopus.com/inward/record.url?scp=0024670902&partnerID=8YFLogxK
U2 - 10.1128/jb.171.5.2563-2572.1989
DO - 10.1128/jb.171.5.2563-2572.1989
M3 - ???researchoutput.researchoutputtypes.contributiontojournal.article???
C2 - 2523380
AN - SCOPUS:0024670902
SN - 0021-9193
VL - 171
SP - 2563
EP - 2572
JO - Journal of Bacteriology
JF - Journal of Bacteriology
IS - 5
ER -