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YoeB toxin is activated during thermal stress.

Janssen BD, Garza-Sánchez F, Hayes CS - Microbiologyopen (2015)

Bottom Line: Moreover, heat-activated YoeB does not induce growth arrest nor does it suppress global protein synthesis.In fact, E. coli cells proliferate more rapidly at elevated temperatures and instantaneously accelerate their growth rate in response to acute heat shock.We propose that heat-activated YoeB may serve a quality control function, facilitating the recycling of stalled translation complexes through ribosome rescue pathways.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, California.

No MeSH data available.


Related in: MedlinePlus

Overexpression of yefM suppresses temperature-induced A-site mRNA cleavage. (A) flag-(m)ybeL-PP transcripts were expressed in ssrA−rnb+ and ssrA−Δrnb backgrounds at 37°C and 42°C. Where indicated (+), the yefM or relB antitoxin genes were overexpressed from a plasmid-borne arabinose-inducible promoter. (B) flag-(m)ybeL-PP transcripts were expressed in ssrA−rnb+ and ssrA−Δrnb backgrounds at 37°C. Where indicated (+), the yoeB or yefM-yoeB genes were overexpressed from plasmid-borne arabinose-inducible promoters. The migration positions of stop codon truncated messages are indicated by control transcripts prepared by in vitro transcription. The horizontal arrows indicate an additional truncated transcript that is produced during growth at 42°C (A) or yoeB induction without yefM (B).
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fig03: Overexpression of yefM suppresses temperature-induced A-site mRNA cleavage. (A) flag-(m)ybeL-PP transcripts were expressed in ssrA−rnb+ and ssrA−Δrnb backgrounds at 37°C and 42°C. Where indicated (+), the yefM or relB antitoxin genes were overexpressed from a plasmid-borne arabinose-inducible promoter. (B) flag-(m)ybeL-PP transcripts were expressed in ssrA−rnb+ and ssrA−Δrnb backgrounds at 37°C. Where indicated (+), the yoeB or yefM-yoeB genes were overexpressed from plasmid-borne arabinose-inducible promoters. The migration positions of stop codon truncated messages are indicated by control transcripts prepared by in vitro transcription. The horizontal arrows indicate an additional truncated transcript that is produced during growth at 42°C (A) or yoeB induction without yefM (B).

Mentions: The YefM antitoxin specifically binds to YoeB toxin and neutralizes its RNase activity (Cherny et al. 2005; Kamada and Hanaoka 2005; Feng et al. 2013). Therefore, if heat-induced transcript cleavage is mediated by YoeB, then the activity should be specifically blocked by yefM overexpression. We cloned yefM under control of the PBAD promoter and induced expression in cells that coexpress flag-(m)ybeL-PP. In cells grown at 37°C, yefM expression had no discernible effect on mRNA cleavage (Fig.3A, lanes 2, 3, 6, and 7). However, yefM expression suppressed mRNA cleavage in ssrA−Δrnb cells at 42°C (Fig.3A, lane 8 and 9). This suppressive effect was specific because induction of relB, which encodes the antitoxin for RelE toxin, had little effect on heat-induced mRNase activity (Fig.3A, bottom blot). We then expressed yoeB from a plasmid-borne PBAD promoter to determine whether the toxin cleaves flag-(m)ybeL-PP transcripts. The two major truncated species that accumulate during thermal stress were also produced in response to yoeB induction at 37°C (Fig.3B, lanes 2 and 4). Thus, the heat-induced mRNA activity can be recapitulated by yoeB expression at lower temperature. In contrast, expression of the entire yefM-yoeB operon from the same plasmid vector did not induce mRNA cleavage (Fig.3B, lanes 3 and 5). Taken together, these data indicate that YoeB is responsible for the heat-induced mRNase activity.


YoeB toxin is activated during thermal stress.

Janssen BD, Garza-Sánchez F, Hayes CS - Microbiologyopen (2015)

Overexpression of yefM suppresses temperature-induced A-site mRNA cleavage. (A) flag-(m)ybeL-PP transcripts were expressed in ssrA−rnb+ and ssrA−Δrnb backgrounds at 37°C and 42°C. Where indicated (+), the yefM or relB antitoxin genes were overexpressed from a plasmid-borne arabinose-inducible promoter. (B) flag-(m)ybeL-PP transcripts were expressed in ssrA−rnb+ and ssrA−Δrnb backgrounds at 37°C. Where indicated (+), the yoeB or yefM-yoeB genes were overexpressed from plasmid-borne arabinose-inducible promoters. The migration positions of stop codon truncated messages are indicated by control transcripts prepared by in vitro transcription. The horizontal arrows indicate an additional truncated transcript that is produced during growth at 42°C (A) or yoeB induction without yefM (B).
© Copyright Policy - open-access
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4554461&req=5

fig03: Overexpression of yefM suppresses temperature-induced A-site mRNA cleavage. (A) flag-(m)ybeL-PP transcripts were expressed in ssrA−rnb+ and ssrA−Δrnb backgrounds at 37°C and 42°C. Where indicated (+), the yefM or relB antitoxin genes were overexpressed from a plasmid-borne arabinose-inducible promoter. (B) flag-(m)ybeL-PP transcripts were expressed in ssrA−rnb+ and ssrA−Δrnb backgrounds at 37°C. Where indicated (+), the yoeB or yefM-yoeB genes were overexpressed from plasmid-borne arabinose-inducible promoters. The migration positions of stop codon truncated messages are indicated by control transcripts prepared by in vitro transcription. The horizontal arrows indicate an additional truncated transcript that is produced during growth at 42°C (A) or yoeB induction without yefM (B).
Mentions: The YefM antitoxin specifically binds to YoeB toxin and neutralizes its RNase activity (Cherny et al. 2005; Kamada and Hanaoka 2005; Feng et al. 2013). Therefore, if heat-induced transcript cleavage is mediated by YoeB, then the activity should be specifically blocked by yefM overexpression. We cloned yefM under control of the PBAD promoter and induced expression in cells that coexpress flag-(m)ybeL-PP. In cells grown at 37°C, yefM expression had no discernible effect on mRNA cleavage (Fig.3A, lanes 2, 3, 6, and 7). However, yefM expression suppressed mRNA cleavage in ssrA−Δrnb cells at 42°C (Fig.3A, lane 8 and 9). This suppressive effect was specific because induction of relB, which encodes the antitoxin for RelE toxin, had little effect on heat-induced mRNase activity (Fig.3A, bottom blot). We then expressed yoeB from a plasmid-borne PBAD promoter to determine whether the toxin cleaves flag-(m)ybeL-PP transcripts. The two major truncated species that accumulate during thermal stress were also produced in response to yoeB induction at 37°C (Fig.3B, lanes 2 and 4). Thus, the heat-induced mRNA activity can be recapitulated by yoeB expression at lower temperature. In contrast, expression of the entire yefM-yoeB operon from the same plasmid vector did not induce mRNA cleavage (Fig.3B, lanes 3 and 5). Taken together, these data indicate that YoeB is responsible for the heat-induced mRNase activity.

Bottom Line: Moreover, heat-activated YoeB does not induce growth arrest nor does it suppress global protein synthesis.In fact, E. coli cells proliferate more rapidly at elevated temperatures and instantaneously accelerate their growth rate in response to acute heat shock.We propose that heat-activated YoeB may serve a quality control function, facilitating the recycling of stalled translation complexes through ribosome rescue pathways.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular, Cellular and Developmental Biology, University of California, Santa Barbara, Santa Barbara, California.

No MeSH data available.


Related in: MedlinePlus