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Transcription start site mapping and small RNA profiling of Leptospira biflexa serovar Patoc

Cheah HL, Ahmed SA, Tang TH

World J Microbiol Biotechnol, 2023 Feb 21;39(4):104.
PMID: 36808011 DOI: 10.1007/s11274-023-03540-4

Leptospirosis is an emerging zoonotic disease caused by bacterial species of the genus Leptospira. However, the regulatory mechanisms and pathways underlying the adaptation of pathogenic and non-pathogenic Leptospira spp. in different environmental conditions remain elusive. Leptospira biflexa is a non-pathogenic species of Leptospira that lives exclusively in a natural environment. It is an ideal model not only for exploring molecular mechanisms underlying the environmental survival of Leptospira species but also for identifying virulence factors unique to Leptospira's pathogenic species. In this study, we aim to establish the transcription start site (TSS) landscape and the small RNA (sRNA) profile of L. biflexa serovar Patoc grown to exponential and stationary phases via differential RNA-seq (dRNA-seq) and small RNA-seq (sRNA-seq) analyses, respectively. Our dRNA-seq analysis uncovered a total of 2726 TSSs, which are also used to identify other elements, e.g., promoter and untranslated regions (UTRs). Besides, our sRNA-seq analysis revealed a total of 603 sRNA candidates, comprising 16 promoter-associated sRNAs, 184 5'UTR-derived sRNAs, 230 true intergenic sRNAs, 136 5'UTR-antisense sRNAs, and 130 open reading frame (ORF)-antisense sRNAs. In summary, these findings reflect the transcriptional complexity of L. biflexa serovar Patoc under different growth conditions and help to facilitate our understanding of regulatory networks in L. biflexa. To the best of our knowledge, this is the first study reporting the TSS landscape of L. biflexa. The TSS and sRNA landscapes of L. biflexa can also be compared with its pathogenic counterparts, e.g., L. borgpetersenii and L. interrogans, to identify features contributing to their environmental survival and virulence.

Matched MeSH terms: RNA, Small Untranslated*
Bacterial sRNAs: regulation in stress

Hoe CH, Raabe CA, Rozhdestvensky TS, Tang TH

Int J Med Microbiol, 2013 Jul;303(5):217-29.
PMID: 23660175 DOI: 10.1016/j.ijmm.2013.04.002

Bacteria are often exposed to a hostile environment and have developed a plethora of cellular processes in order to survive. A burgeoning list of small non-coding RNAs (sRNAs) has been identified and reported to orchestrate crucial stress responses in bacteria. Among them, cis-encoded sRNA, trans-encoded sRNA, and 5'-untranslated regions (UTRs) of the protein coding sequence are influential in the bacterial response to environmental cues, such as fluctuation of temperature and pH as well as other stress conditions. This review summarizes the role of bacterial sRNAs in modulating selected stress conditions and highlights the alliance between stress response and clustered regularly interspaced short palindromic repeats (CRISPR) in bacterial defense.

Matched MeSH terms: RNA, Small Untranslated/genetics; RNA, Small Untranslated/metabolism*
Fulltext Biases in small RNA deep sequencing data

Raabe CA, Tang TH, Brosius J, Rozhdestvensky TS

Nucleic Acids Res, 2014 Feb;42(3):1414-26.
PMID: 24198247 DOI: 10.1093/nar/gkt1021

High-throughput RNA sequencing (RNA-seq) is considered a powerful tool for novel gene discovery and fine-tuned transcriptional profiling. The digital nature of RNA-seq is also believed to simplify meta-analysis and to reduce background noise associated with hybridization-based approaches. The development of multiplex sequencing enables efficient and economic parallel analysis of gene expression. In addition, RNA-seq is of particular value when low RNA expression or modest changes between samples are monitored. However, recent data uncovered severe bias in the sequencing of small non-protein coding RNA (small RNA-seq or sRNA-seq), such that the expression levels of some RNAs appeared to be artificially enhanced and others diminished or even undetectable. The use of different adapters and barcodes during ligation as well as complex RNA structures and modifications drastically influence cDNA synthesis efficacies and exemplify sources of bias in deep sequencing. In addition, variable specific RNA G/C-content is associated with unequal polymerase chain reaction amplification efficiencies. Given the central importance of RNA-seq to molecular biology and personalized medicine, we review recent findings that challenge small non-protein coding RNA-seq data and suggest approaches and precautions to overcome or minimize bias.

Matched MeSH terms: RNA, Small Untranslated/metabolism*; RNA, Small Untranslated/chemistry
Mapping and identification of potential target genes from short-RNA seq for the control of Pieris rapae larvae

Senthil Kumar R, Srinivasan R, Rawdzah MA, Malini P

Genomics, 2020 03;112(2):1464-1476.
PMID: 31450005 DOI: 10.1016/j.ygeno.2019.08.017

Pieris rapae is a serious pest of brassicas worldwide. We performed de novo assembly of P. rapae transcriptome by next-generation sequencing and assembled approximately 65,727,422 clean paired-end reads into 32,118 unigenes, of which 13,585 were mapped to 255 pathways in the KEGG database. A total of 6173 novel transcripts were identified from reads directly mapped to P. rapae genome. Additionally, 1490 SSRs, 301,377 SNPs, and 29,284 InDels were identified as potential molecular markers to explore polymorphism within P. rapae populations. We screened and mapped 36 transcripts related to OBP, CSP, SNMP, PBAN, and OR. We analyzed the expression profiles of 7 selected genes involved in pheromone transport and degradation by quantitative real-time PCR; these genes are sex-specific and differentially expressed in the developmental stages. Overall, the comprehensive transcriptome resources described in this study could help understand and identify molecular targets particularly reproduction-related genes for developing effective P. rapae management tools.

Matched MeSH terms: RNA, Small Untranslated/genetics*; RNA, Small Untranslated/metabolism
Argonaute: The executor of small RNA function

Azlan A, Dzaki N, Azzam G

J Genet Genomics, 2016 08 20;43(8):481-94.
PMID: 27569398 DOI: 10.1016/j.jgg.2016.06.002

The discovery of small non-coding RNAs - microRNA (miRNA), short interfering RNA (siRNA) and PIWI-interacting RNA (piRNA) - represents one of the most exciting frontiers in biology specifically on the mechanism of gene regulation. In order to execute their functions, these small RNAs require physical interactions with their protein partners, the Argonaute (AGO) family proteins. Over the years, numerous studies have made tremendous progress on understanding the roles of AGO in gene silencing in various organisms. In this review, we summarize recent progress of AGO-mediated gene silencing and other cellular processes in which AGO proteins have been implicated with a particular focus on progress made in flies, humans and other model organisms as compliment.

Matched MeSH terms: RNA, Small Untranslated/genetics*
Fulltext Aging Induces Profound Changes in sncRNA in Rat Sperm and These Changes Are Modified by Perinatal Exposure to Environmental Flame Retardant

Suvorov A, Pilsner JR, Naumov V, Shtratnikova V, Zheludkevich A, Gerasimov E, et al.

Int J Mol Sci, 2020 Nov 04;21(21).
PMID: 33158036 DOI: 10.3390/ijms21218252

Advanced paternal age at fertilization is a risk factor for multiple disorders in offspring and may be linked to age-related epigenetic changes in the father's sperm. An understanding of aging-related epigenetic changes in sperm and environmental factors that modify such changes is needed. Here, we characterize changes in sperm small non-coding RNA (sncRNA) between young pubertal and mature rats. We also analyze the modification of these changes by exposure to environmental xenobiotic 2,2',4,4'-tetrabromodiphenyl ether (BDE-47). sncRNA libraries prepared from epididymal spermatozoa were sequenced and analyzed using DESeq 2. The distribution of small RNA fractions changed with age, with fractions mapping to rRNA and lncRNA decreasing and fractions mapping to tRNA and miRNA increasing. In total, 249 miRNA, 908 piRNA and 227 tRNA-derived RNA were differentially expressed (twofold change, false discovery rate (FDR) p ≤ 0.05) between age groups in control animals. Differentially expressed miRNA and piRNA were enriched for protein-coding targets involved in development and metabolism, while piRNA were enriched for long terminal repeat (LTR) targets. BDE-47 accelerated age-dependent changes in sncRNA in younger animals, decelerated these changes in older animals and increased the variance in expression of all sncRNA. Our results indicate that the natural aging process has profound effects on sperm sncRNA profiles and this effect may be modified by environmental exposure.

Matched MeSH terms: RNA, Small Untranslated/genetics*; RNA, Small Untranslated/metabolism
Fulltext miRNAS as potential biomarkers in head and neck squamous cell carcinoma diagnostics

Cheah Yoke Kqueen, Yaghma Masood, Nurul Syakima Ab Mutalib, Sethu Thakachy Subha, Norhafizah Mohtarrudin

Malaysian Journal of Medicine and Health Sciences, 2019;15(108):9-9.
MyJurnal

MicroRNAs (miRNAs) are small noncoding RNAs that involved in various normal and cancer-related cellular pro-cesses. Studies on expression profiling of miRNAs have been performed and the data showed that some miRNAs are up-regulated or down-regulated in cancer. miRNAs play a crucial role in HNSCC development, metastasis, prognosis and survival rate. Several studies have been conducted previously to investigate that use of miRNAs as the biomark-ers in disease diagnostic/prognostic and potential therapeutic targets management that may improve the outcomes of HNSCC. Our previous study revealed that upregulation of oncogenic miRNAs including hsa-miR-181a-2*, hsa-miR-29b-1*, hsa-miR-181a, hsa-miR-181b, hsa-miR-744, hsa-miR-1271 and hsa-miR-221* were able to distinguish HNSCC from normal samples. These miRNAs may contribute in a simple profiling strategy to identify individuals at higher risk of developing head and neck cancers, thus helping in the elucidation of the molecular mechanisms involved in head and neck cancer pathogenesis.

Matched MeSH terms: RNA, Small Untranslated
Association between microRNA-196A2 and microRNA-146A polymorphisms and progression to cirrhosis and hepatocellular carcinoma in patients with viral hepatitis B

Riazalhosseini B, Mohamed Z, Apalasamy YD, Eng HS, Mohamed R

Pharmacogenet Genomics, 2016 Feb;26(2):74-9.
PMID: 26529280 DOI: 10.1097/FPC.0000000000000187

MicroRNAs (miRNAs) are small noncoding RNAs that have been implicated in mechanisms underlying various types of cancers including hepatocellular carcinoma (HCC). Reports have indicated that single nucleotide polymorphisms in miRNA-196A2 and miRNA-146A genes may contribute to the risk of progression of hepatitis B virus (HBV) infection to cirrhosis and HCC. This study aimed to examine the effect of miRNA-196A2 and miRNA-146A polymorphisms on the progression of HBV infection to cirrhosis and/or HCC in HBV patients in the Malaysian population.

Matched MeSH terms: RNA, Small Untranslated
Fulltext A small RNA decreases the sensitivity of Shigella sonnei to norfloxacin

Gan IN, Tan HS

BMC Res Notes, 2019 Feb 21;12(1):97.
PMID: 30791948 DOI: 10.1186/s13104-019-4124-4

OBJECTIVES: Shigella is a human pathogen that causes shigellosis, an acute invasive intestinal infection. Recent studies in the model bacterium Escherichia coli (E. coli) provided evidence that small regulatory RNAs (sRNAs) can contribute to antimicrobial resistance or susceptibility. One of the sRNAs is SdsR, which increases sensitivity of E. coli against fluoroquinolone by repressing the drug efflux pump, TolC. However, no reports exist about the effect of SdsR on fluoroquinolone resistance in Shigella sonnei (S. sonnei). In this study, we established the effect of SdsR on the sensitivity of S. sonnei to norfloxacin.
DATA DESCRIPTION: We tested the effects of SdsR and SdsRv2 on fluoroquinolone resistance in S. sonnei in vivo. SdsRv2 is a synthetic version which promotes higher binding stability to tolC mRNA. Overexpression of either SdsR or SdsRv2 lowers the expression of tolC mRNA. Interestingly, SdsR and SdsRv2 promote the growth of S. sonnei in the presence of a sub-inhibitory concentration of norfloxacin. Mutant carrying SdsRv2 showed the highest growth advantage. This phenotype is opposite to the effect of SdsR reported in E. coli. This study is an example that demonstrates the difference in the phenotypic effect of a highly conserved sRNA in two closely related bacteria.

Matched MeSH terms: RNA, Small Untranslated/drug effects*
RNomic identification and evaluation of npcTB_6715, a non-protein-coding RNA gene as a potential biomarker for the detection of Mycobacterium tuberculosis

Kanniappan P, Ahmed SA, Rajasekaram G, Marimuthu C, Ch'ng ES, Lee LP, et al.

J Cell Mol Med, 2017 10;21(10):2276-2283.
PMID: 28756649 DOI: 10.1111/jcmm.13148

Technological advances in RNA biology greatly improved transcriptome profiling during the last two decades. Besides the discovery of many small RNAs (sRNA) that are involved in the physiological and pathophysiological regulation of various cellular circuits, it becomes evident that the corresponding RNA genes might also serve as potential biomarkers to monitor the progression of disease and treatment. sRNA gene candidate npcTB_6715 was previously identified via experimental RNomic (unpublished data), and we report its application as potential biomarker for the detection of Mycobacterium tuberculosis (MTB) in patient samples. For proof of principle, we developed a multiplex PCR assay and report its validation with 500 clinical cultures, positive for Mycobacteria. The analysis revealed 98.9% sensitivity, 96.1% specificity, positive and negative predictive values of 98.6% and 96.8%, respectively. These results underscore the diagnostic value of the sRNA gene as diagnostic marker for the specific detection of MTB in clinical samples. Its successful application and the general ease of PCR-based detection compared to standard bacterial culture techniques might be the first step towards 'point-of-care' diagnostics of Mycobacteria. To the best of our knowledge, this is the first time for the design of diagnostic applications based on sRNA genes, in Mycobacteria.

Matched MeSH terms: RNA, Small Untranslated/genetics*
Fulltext Genome-wide mapping of the RNA targets of the Pseudomonas aeruginosa riboregulatory protein RsmN

Romero M, Silistre H, Lovelock L, Wright VJ, Chan KG, Hong KW, et al.

Nucleic Acids Res, 2018 Jul 27;46(13):6823-6840.
PMID: 29718466 DOI: 10.1093/nar/gky324

Pseudomonads typically carry multiple non-identical alleles of the post-transcriptional regulator rsmA. In Pseudomonas aeruginosa, RsmN is notable in that its structural rearrangement confers distinct and overlapping functions with RsmA. However, little is known about the specificities of RsmN for its target RNAs and overall impact on the biology of this pathogen. We purified and mapped 503 transcripts directly bound by RsmN in P. aeruginosa. About 200 of the mRNAs identified encode proteins of demonstrated function including some determining acute and chronic virulence traits. For example, RsmN reduces biofilm development both directly and indirectly via multiple pathways, involving control of Pel exopolysaccharide biosynthesis and c-di-GMP levels. The RsmN targets identified are also shared with RsmA, although deletion of rsmN generally results in less pronounced phenotypes than those observed for ΔrsmA or ΔrsmArsmNind mutants, probably as a consequence of different binding affinities. Targets newly identified for the Rsm system include the small non-coding RNA CrcZ involved in carbon catabolite repression, for which differential binding of RsmN and RsmA to specific CrcZ regions is demonstrated. The results presented here provide new insights into the intricacy of riboregulatory networks involving multiple but distinct RsmA homologues.

Matched MeSH terms: RNA, Small Untranslated/metabolism
In silico 'fishing' using known small regulatory RNA (sRNA) candidates as the decoy from Escherichia coli, Salmonella typhi and Salmonella typhimurium manifested 14 novel sRNA candidates in the orthologous region of Proteus mirabilis

KishanRaj S, Sumitha S, Siventhiran B, Thiviyaa O, Sathasivam KV, Xavier R, et al.

Mol Biol Rep, 2018 Dec;45(6):2333-2343.
PMID: 30284142 DOI: 10.1007/s11033-018-4397-z

Proteus mirabilis, a gram-negative bacterium of the family Enterobacteriaceae, is a leading cause of urinary tract infection (UTI) with rapid development of multi-drug resistance. Identification of small regulatory RNAs (sRNAs), which belongs to a class of RNAs that do not translate into a protein, could permit the comprehension of the regulatory roles this molecules play in mediating pathogenesis and multi-drug resistance of the organism. In this study, comparative sRNA analysis across three different members of Enterobacteriaceae (Escherichia coli, Salmonella typhi and Salmonella typhimurium) was carried out to identify the sRNA homologs in P. mirabilis. A total of 232 sRNA genes that were reported in E. coli, S. typhi and S. typhimurium were subjected to comparative analysis against P. mirabilis HI4320 genome. We report the detection of 14 sRNA candidates, conserved in the orthologous regions of P. mirabilis, that are not included in Rfam database. Northern-blot analysis was carried out for selected three sRNA candidates from the current investigation and three known sRNA from Rfam of P. mirabilis. The expression pattern of the six sRNA candidates shows that they are growth stage-dependant. To the best of our knowledge, this is the first report on the identification of sRNA candidates in P. mirabilis.

Matched MeSH terms: RNA, Small Untranslated/genetics*

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