Project description:RNA-binding proteins (RBPs) play important roles in bacterial gene expression and physiology but their true number and functional scope remain little understood even in model microbes. To advance global RBP discovery in bacteria, we here establish glycerol gradient sedimentation with RNase treatment and mass spectrometry (GradR). Applied to Salmonella enterica, GradR confirms many known RBPs by their RNase-sensitive sedimentation profiles, and discovers the FopA protein as a new member of the emerging family of FinO/ProQ-like RBPs. FopA, encoded on resistance plasmid pCol1B9, primarily targets a small RNA associated with plasmid replication. The target suite of FopA dramatically differs from the related global RBP ProQ, revealing context-dependent selective RNA recognition by FinO-domain RBPs. Numerous other unexpected RNase-induced changes in gradient profiles suggest that cellular RNA helps to organize macromolecular complexes in bacteria. By enabling poly(A)-independent generic RBP discovery, GradR provides an important element for building a comprehensive catalogue of microbial RBPs.
Project description:RNA-binding proteins (RBPs) play important roles in bacterial gene expression and physiology but their true number and functional scope remain little understood even in model microbes. To advance global RBP discovery in bacteria, we here establish glycerol gradient sedimentation with RNase treatment and mass spectrometry (GradR). Applied to Salmonella enterica, GradR confirms many known RBPs such as CsrA, Hfq, and ProQ by their RNase-sensitive sedimentation profiles, and discovers the FopA protein as a new member of the emerging family of FinO/ProQ-like RBPs. FopA, encoded on resistance plasmid pCol1B9, primarily targets a small RNA associated with plasmid replication. The target suite of FopA dramatically differs from the related global RBP ProQ, revealing context-dependent selective RNA recognition by FinO-domain RBPs. Numerous other unexpected RNase-induced changes in gradient profiles suggest that cellular RNA helps to organize macromolecular complexes in bacteria. By enabling poly(A)-independent generic RBP discovery, GradR provides an important element in the quest to build a comprehensive catalog of microbial RBPs.
Project description:Two types of RNA:DNA associations can lead to genome instability: the formation of R-loops during transcription and the incorporation of ribonucleotide monophosphates (rNMPs) into DNA during replication. Both ribonuclease (RNase) H1 and RNase H2 degrade the RNA component of R-loops, whereas only RNase H2 can remove one or a few rNMPs from DNA. We performed high-resolution mapping of mitotic recombination events throughout the yeast genome in diploid strains of Saccharomyces cerevisiae lacking RNase H1 (rnh1Δ), RNase H2 (rnh201Δ), or both RNase H1 and RNase H2 (rnh1Δ rnh201Δ). We found little effect on recombination in the rnh1Δ strain, but elevated recombination in both the rnh201Δ and the double-mutant strains; levels of recombination in the double mutant were about 50% higher than in the rnh201 single-mutant strain. An rnh201Δ mutant that additionally contained a mutation that reduces rNMP incorporation by DNA polymerase ε (pol2-M644L) had a level of instability similar to that observed in the presence of wild-type Polε. This result suggests that the elevated recombination observed in the absence of only RNase H2 is primarily a consequence of R loops rather than misincorporated rNMPs.
Project description:Male sterility is an important trait in hybrid crop breeding. Thermo-sensitive genic male sterility (TGMS) lines, which are male-sterile at restrictive (high) temperatures but convert to male-fertile at permissive (low) temperatures, have been widely utilized in two-line hybrid rice breeding3. However, the molecular mechanism underlying TGMS remains unclear. Here we show that the rice (Oryza sativa L.) thermo-sensitive genic male sterile gene 5 (tms5) locus, which in 2010 was present in cultivars occupying more than 70% (2.4 million hectares) of two-line hybrid rice-growing land in China, confers the TGMS trait through a loss-of-function mutation of RNase ZS1, resulting in failure to mediate mRNA decay of three temperature-responsive ubiquitin fusion ribosomal protein L40 genes (UbL40). TMS5 encodes an evolutionarily conserved endonuclease, RNase ZS1. RNase ZS1 can process tRNAs in vitro, but does not do so in vivo due to its localization in the cytoplasm. Defective RNase ZS1 in tms5 plants leads to over-accumulation of UbL401, UbL402 and UbL404 mRNAs at restrictive but not permissive temperatures. Furthermore, over-expression of UbL401 and UbL404 in wild-type plants causes male sterility, while knockdown of UbL401 and UbL404 in tms5 partially restores its fertility. Our results uncover a novel mechanism of RNase ZS1-mediated UbL40 mRNA decay which controls TGMS in rice and has potential applications in hybrid breeding not only of rice but also of other crops.
Project description:The purpose of this study was to compare changes in translation (using Gradient Encoding, described below) to changes in mRNA abundance. Lysates of wildtype v-Abl transformed pre-B cells harvested before and after 12 hours of treatment either with 2.5 uM imatinib, a v-Abl kinase inhibitor, or 10ng/mL (10.9 nM) rapamycin, an mTOR inhibitor, were fractionated by sedimentation through linear sucrose gradients. Gradient fractions were encoded such that the mRNA from successive fractions was labeled with increasing ratios of Cy5 to Cy3. mRNAs derived from fractions in the lighter portion of the gradient therefore have a lower Cy5 to Cy3 ratio, whereas those deeper in the gradient have a higher Cy5 to Cy3 ratio. The ratio of Cy5 to Cy3 for each mRNA therefore reflects its average position within the gradient. We thus encoded the sedimentation rate of each mRNA across the entire gradient. The resulting ratios were quantitatively measured for each mRNA species by hybridization to DNA microarrays, and related to the 260 nm absorbance peaks representing different numbers of ribosomes bound per mRNA Compound Based Treatment: wildtype v-Abl transformed pre-B cells were treated with imatinib mesylate (IMA), rapamycin (RAP) or nothing (NONE)
Project description:Male sterility is an important trait in hybrid crop breeding. Thermo-sensitive genic male sterility (TGMS) lines, which are male-sterile at restrictive (high) temperatures but convert to male-fertile at permissive (low) temperatures, have been widely utilized in two-line hybrid rice breeding. However, the molecular mechanism underlying TGMS remains unclear. Here we show that the rice (Oryza sativa L.) thermo-sensitive genic male sterile gene 5 (tms5) locus, which in 2010 was present in cultivars occupying more than 80% (2.6 million hectares) of two-line hybrid rice-growing land in China, confers the TGMS trait through a loss-of-function mutation of RNase ZS1, resulting in failure to mediate mRNA decay of three temperature-responsive ubiquitin fusion ribosomal protein L40 genes (UbL40) genes. RNase ZS1, a member of the evolutionarily conserved endonuclease, processed tRNAs in vitro, but does not do so in vivo due to its localization in the cytoplasm. Defective RNase ZS1 in tms5 plants leads to over-accumulation of UbL401, UbL402 and UbL404 mRNAs at restrictive but not permissive temperatures. Over-expression of UbL401 and UbL404 in wild-type plants caused male sterility, whereas knockdown of UbL401 and UbL404 in tms5 plants partially restored the male fertility at restrictive temperatures. Our results uncover a novel mechanism of RNase ZS1-mediated UbL40 mRNA decay which controls TGMS in rice and has potential applications not only of rice but also of other crops.
Project description:Male sterility is an important trait in hybrid crop breeding. Thermo-sensitive genic male sterility (TGMS) lines, which are male-sterile at restrictive (high) temperatures but convert to male-fertile at permissive (low) temperatures, have been widely utilized in two-line hybrid rice breeding3. However, the molecular mechanism underlying TGMS remains unclear. Here we show that the rice (Oryza sativa L.) thermo-sensitive genic male sterile gene 5 (tms5) locus, which in 2010 was present in cultivars occupying more than 70% (2.4 million hectares) of two-line hybrid rice-growing land in China, confers the TGMS trait through a loss-of-function mutation of RNase ZS1, resulting in failure to mediate mRNA decay of three temperature-responsive ubiquitin fusion ribosomal protein L40 genes (UbL40). TMS5 encodes an evolutionarily conserved endonuclease, RNase ZS1. RNase ZS1 can process tRNAs in vitro, but does not do so in vivo due to its localization in the cytoplasm. Defective RNase ZS1 in tms5 plants leads to over-accumulation of UbL401, UbL402 and UbL404 mRNAs at restrictive but not permissive temperatures. Furthermore, over-expression of UbL401 and UbL404 in wild-type plants causes male sterility, while knockdown of UbL401 and UbL404 in tms5 partially restores its fertility. Our results uncover a novel mechanism of RNase ZS1-mediated UbL40 mRNA decay which controls TGMS in rice and has potential applications in hybrid breeding not only of rice but also of other crops. Examination of differences in mRNA accumulation between 93-11, NIL5 and NIL8.
Project description:The purpose of this study was to compare changes in translation (using Gradient Encoding, described below) to changes in mRNA abundance. Lysates of wildtype v-Abl transformed pre-B cells harvested before and after 12 hours of treatment either with 2.5 uM imatinib, a v-Abl kinase inhibitor, or 10ng/mL (10.9 nM) rapamycin, an mTOR inhibitor, were fractionated by sedimentation through linear sucrose gradients. Gradient fractions were encoded such that the mRNA from successive fractions was labeled with increasing ratios of Cy5 to Cy3. mRNAs derived from fractions in the lighter portion of the gradient therefore have a lower Cy5 to Cy3 ratio, whereas those deeper in the gradient have a higher Cy5 to Cy3 ratio. The ratio of Cy5 to Cy3 for each mRNA therefore reflects its average position within the gradient. We thus encoded the sedimentation rate of each mRNA across the entire gradient. The resulting ratios were quantitatively measured for each mRNA species by hybridization to DNA microarrays, and related to the 260 nm absorbance peaks representing different numbers of ribosomes bound per mRNA Compound Based Treatment: wildtype v-Abl transformed pre-B cells were treated with imatinib mesylate (IMA), rapamycin (RAP) or nothing (NONE) compound_treatment_design