Abstract
Transcription of the tryptophanase (tna) operon of Escherichia coli is regulated by catabolite repression and tryptophan-induced transcription antitermination. Induction results from ribosome stalling after translation of tnaC, the coding region for a 24-residue leader peptide. The last sense codon of tnaC, proline codon 24 (CCU), is translated by tRNA2Pro. We analyzed the consequences of overexpression of tnaC from a multicopy plasmid and observed that under inducing conditions more than 60% of the tRNA 2Pro in the cell was sequestered in ribosomes as TnaC-tRNA2Pro. The half-life of this TnaC-tRNA 2Pro was shown to be 10 to 15 min under these conditions. Plasmid-mediated overexpression of tnaC, under inducing conditions, reduced cell growth rate appreciably. Increasing the tRNA2Pro level relieved this growth inhibition, suggesting that depletion of this tRNA was primarily responsible for the growth rate reduction. Growth inhibition was not relieved by overexpression of tRNA1Pro, a tRNA Pro that translates CCG, but not CCU. Replacing the Pro24CCU codon of tnaC by Pro24CCG, a Pro codon translated by tRNA1Pro, also led to growth rate reduction, and this reduction was relieved by overexpression of tRNA1Pro. These findings establish that the growth inhibition caused by tnaC overexpression during induction by tryptophan is primarily a consequence of tRNAPro depletion, resulting from TnaC-tRNAPro retention within stalled, translating ribosomes.
| Original language | English |
|---|---|
| Pages (from-to) | 1892-1898 |
| Number of pages | 7 |
| Journal | Journal of Bacteriology |
| Volume | 188 |
| Issue number | 5 |
| DOIs | |
| State | Published - Mar 1 2006 |
| Externally published | Yes |
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ASJC Scopus subject areas
- Applied Microbiology and Biotechnology
- Immunology
Cite this
Overexpression of tnaC of Escherichia coli inhibits growth by depleting tRNA2Pro availability. / Gong, Ming; Gong, Feng; Yanofsky, Charles.
In: Journal of Bacteriology, Vol. 188, No. 5, 01.03.2006, p. 1892-1898.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Overexpression of tnaC of Escherichia coli inhibits growth by depleting tRNA2Pro availability
AU - Gong, Ming
AU - Gong, Feng
AU - Yanofsky, Charles
PY - 2006/3/1
Y1 - 2006/3/1
N2 - Transcription of the tryptophanase (tna) operon of Escherichia coli is regulated by catabolite repression and tryptophan-induced transcription antitermination. Induction results from ribosome stalling after translation of tnaC, the coding region for a 24-residue leader peptide. The last sense codon of tnaC, proline codon 24 (CCU), is translated by tRNA2Pro. We analyzed the consequences of overexpression of tnaC from a multicopy plasmid and observed that under inducing conditions more than 60% of the tRNA 2Pro in the cell was sequestered in ribosomes as TnaC-tRNA2Pro. The half-life of this TnaC-tRNA 2Pro was shown to be 10 to 15 min under these conditions. Plasmid-mediated overexpression of tnaC, under inducing conditions, reduced cell growth rate appreciably. Increasing the tRNA2Pro level relieved this growth inhibition, suggesting that depletion of this tRNA was primarily responsible for the growth rate reduction. Growth inhibition was not relieved by overexpression of tRNA1Pro, a tRNA Pro that translates CCG, but not CCU. Replacing the Pro24CCU codon of tnaC by Pro24CCG, a Pro codon translated by tRNA1Pro, also led to growth rate reduction, and this reduction was relieved by overexpression of tRNA1Pro. These findings establish that the growth inhibition caused by tnaC overexpression during induction by tryptophan is primarily a consequence of tRNAPro depletion, resulting from TnaC-tRNAPro retention within stalled, translating ribosomes.
AB - Transcription of the tryptophanase (tna) operon of Escherichia coli is regulated by catabolite repression and tryptophan-induced transcription antitermination. Induction results from ribosome stalling after translation of tnaC, the coding region for a 24-residue leader peptide. The last sense codon of tnaC, proline codon 24 (CCU), is translated by tRNA2Pro. We analyzed the consequences of overexpression of tnaC from a multicopy plasmid and observed that under inducing conditions more than 60% of the tRNA 2Pro in the cell was sequestered in ribosomes as TnaC-tRNA2Pro. The half-life of this TnaC-tRNA 2Pro was shown to be 10 to 15 min under these conditions. Plasmid-mediated overexpression of tnaC, under inducing conditions, reduced cell growth rate appreciably. Increasing the tRNA2Pro level relieved this growth inhibition, suggesting that depletion of this tRNA was primarily responsible for the growth rate reduction. Growth inhibition was not relieved by overexpression of tRNA1Pro, a tRNA Pro that translates CCG, but not CCU. Replacing the Pro24CCU codon of tnaC by Pro24CCG, a Pro codon translated by tRNA1Pro, also led to growth rate reduction, and this reduction was relieved by overexpression of tRNA1Pro. These findings establish that the growth inhibition caused by tnaC overexpression during induction by tryptophan is primarily a consequence of tRNAPro depletion, resulting from TnaC-tRNAPro retention within stalled, translating ribosomes.
UR - http://www.scopus.com/inward/record.url?scp=33644765213&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=33644765213&partnerID=8YFLogxK
U2 - 10.1128/JB.188.5.1892-1898.2006
DO - 10.1128/JB.188.5.1892-1898.2006
M3 - Article
C2 - 16484200
AN - SCOPUS:33644765213
VL - 188
SP - 1892
EP - 1898
JO - Journal of Bacteriology
JF - Journal of Bacteriology
SN - 0021-9193
IS - 5
ER -