The continuing discoveries of novel classes of RNA modifications in various organisms have raised the need for improving sensitive,convenient,and reliable methods for quantifying RNA modifications.In particular,a subs...The continuing discoveries of novel classes of RNA modifications in various organisms have raised the need for improving sensitive,convenient,and reliable methods for quantifying RNA modifications.In particular,a subset of small RNAs,including microRNAs(miRNAs)and Piwi-interacting RNAs(piRNAs),are modified at their 3'-terminal nucleotides via 2'-0-methylation.However,quantifying the levels of these small RNAs is difficult because 2'-0-methylation at the RNA 3'-terminus inhibits the activity of polyadenylate polymerase and T4 RNA ligase.These two enzymes are indispensable for RNA labeling or ligation in conventional miRNA quantification assays.In this study,we profiled 3'-terminal 2'-0-methyl plant miRNAs in the livers of rice-fed mice by oxidative deep sequencing and detected increasing amounts of plant miRNAs with prolonged oxidation treatment.We further compared the efficiency of stem-loop and poly(A)-tailed RT-qPCR in quantifying plant miRNAs in animal tissues and identified stem-loop RT-qPCR as the only suitable approach.Likewise,stem-loop RT-qPCR was superior to poly(A)-tailed RT-qPCR in quantifying 3'-terminal 2'-0-methyl piRNAs in human seminal plasma.In summary,this study established a standard procedure for quantifying the levels of 3'-terminal 2'-0-methyl miRNAs in plants and piRNAs.Accurate measurement of the 3'-terminal 2'-0-methylation of small RNAs has profound implications for understanding their pathophysiologic roles in biological systems.展开更多
Senecavirus A(SVA)has a positive-sense,single-stranded RNA genome.Its 5´untranslated region harbors an internal ribosome entry site(IRES),comprising 10 larger or smaller stem-loop structures(including a pseudokno...Senecavirus A(SVA)has a positive-sense,single-stranded RNA genome.Its 5´untranslated region harbors an internal ribosome entry site(IRES),comprising 10 larger or smaller stem-loop structures(including a pseudoknot)that have been demonstrated to be well conserved.However,it is still unclear whether each stem-loop subdomain,such as a single stem or loop,is also highly conserved.To clarify this issue in the present study,a set of 29 SVA cDNA clones were constructed by site-directed mutagenesis(SDM)on the IRES.The SDM-modified scenarios included:(1)stem-formed complementary sequences exchanging with each other;(2)loop transversion;(3)loop transition;and(4)point mutations.All cDNA clones were separately transfected into cells for rescuing viable viruses,whereas only four SVAs of interest could be recovered,and were genetically stable during 20 passages.One progeny grew significantly slower than the other three did.The dual-luciferase reporter assay showed that none of the SDM-modified IRESes significantly inhibited the IRES activity.Our previous study indicated that a single motif from any of the ten stem structures,if completely mutated,would cause the failure of virus recovery.Interestingly,our present study revealed three stem structures,whose individual complementary sequences could exchange with each other to rescue sequence-modifying SVAs.Moreover,one apical loop was demonstrated to have the ability to tolerate its own full-length transition,also having no impact on the recovery of sequence-modifying SVA.The present study suggested that not every stem-loop structure was strictly conserved in its conformation,while the full-length IRES itself was well conserved.This provides a new research direction on interaction between the IRES and many factors.展开更多
基金This work was supported by the Fundamental Research Funds for the Central Universities(No.020814380146)National Basic Research Program of China(973 Program)(No.2014CB542300)+1 种基金National Natural Science Foundation of China(Nos.32022015,32001077,31871295,21877060,81250044,81602697,and 81772727)Research Unit of Extracellular Non-Coding RNA,Chinese Academy of Medical Sciences(No.2021RU015).
文摘The continuing discoveries of novel classes of RNA modifications in various organisms have raised the need for improving sensitive,convenient,and reliable methods for quantifying RNA modifications.In particular,a subset of small RNAs,including microRNAs(miRNAs)and Piwi-interacting RNAs(piRNAs),are modified at their 3'-terminal nucleotides via 2'-0-methylation.However,quantifying the levels of these small RNAs is difficult because 2'-0-methylation at the RNA 3'-terminus inhibits the activity of polyadenylate polymerase and T4 RNA ligase.These two enzymes are indispensable for RNA labeling or ligation in conventional miRNA quantification assays.In this study,we profiled 3'-terminal 2'-0-methyl plant miRNAs in the livers of rice-fed mice by oxidative deep sequencing and detected increasing amounts of plant miRNAs with prolonged oxidation treatment.We further compared the efficiency of stem-loop and poly(A)-tailed RT-qPCR in quantifying plant miRNAs in animal tissues and identified stem-loop RT-qPCR as the only suitable approach.Likewise,stem-loop RT-qPCR was superior to poly(A)-tailed RT-qPCR in quantifying 3'-terminal 2'-0-methyl piRNAs in human seminal plasma.In summary,this study established a standard procedure for quantifying the levels of 3'-terminal 2'-0-methyl miRNAs in plants and piRNAs.Accurate measurement of the 3'-terminal 2'-0-methylation of small RNAs has profound implications for understanding their pathophysiologic roles in biological systems.
基金This work was supported by the National Natural Science Found ation of China(32273000)the Qingdao Demonstration Project for People-benefit from Science and Techniques,China(23-2-8-xdny-14nsh and 24-2-8-xdny-4-nsh)+1 种基金the National Program of Undergraduate Innovation and Entrepreneurship,China(202310435039)the Open Project Fund of State Key Laboratory of Microbial Technology,China(M2023-03)。
文摘Senecavirus A(SVA)has a positive-sense,single-stranded RNA genome.Its 5´untranslated region harbors an internal ribosome entry site(IRES),comprising 10 larger or smaller stem-loop structures(including a pseudoknot)that have been demonstrated to be well conserved.However,it is still unclear whether each stem-loop subdomain,such as a single stem or loop,is also highly conserved.To clarify this issue in the present study,a set of 29 SVA cDNA clones were constructed by site-directed mutagenesis(SDM)on the IRES.The SDM-modified scenarios included:(1)stem-formed complementary sequences exchanging with each other;(2)loop transversion;(3)loop transition;and(4)point mutations.All cDNA clones were separately transfected into cells for rescuing viable viruses,whereas only four SVAs of interest could be recovered,and were genetically stable during 20 passages.One progeny grew significantly slower than the other three did.The dual-luciferase reporter assay showed that none of the SDM-modified IRESes significantly inhibited the IRES activity.Our previous study indicated that a single motif from any of the ten stem structures,if completely mutated,would cause the failure of virus recovery.Interestingly,our present study revealed three stem structures,whose individual complementary sequences could exchange with each other to rescue sequence-modifying SVAs.Moreover,one apical loop was demonstrated to have the ability to tolerate its own full-length transition,also having no impact on the recovery of sequence-modifying SVA.The present study suggested that not every stem-loop structure was strictly conserved in its conformation,while the full-length IRES itself was well conserved.This provides a new research direction on interaction between the IRES and many factors.
