scholarly journals Non-coding circular RNAs repertoire and expression profile during Brassica rapa pollen development

2021 ◽  
Author(s):  
Saeid Babaei ◽  
Mohan B. Singh ◽  
Prem L Bhalla

Circular RNAs (circRNAs) are covalently closed long non-coding RNA (lncRNA) molecules generated by the back-splicing of exons from linear precursor mRNAs. Though linear lncRNAs have been shown to play important regulatory roles in diverse biological and developmental processes, little is known about the role of their circular counterparts. In this study, we have performed high-throughput RNA sequencing to delineate the expression profile and potential function of circRNAs during the five stages of pollen development in Brassica rapa. A total of 1180 circRNAs were detected in pollen development, of which 367 showed stage-specific expression patterns. Functional enrichment and metabolic pathway analysis showed that the parent genes of circRNAs were mainly involved in pollen-related molecular and biological processes such as mitotic and meiosis cell division, DNA processes, protein synthesis, protein modification, and polysaccharide biosynthesis. Moreover, by predicting the circRNA-miRNA network from our differentially expressed circRNAs, we found 88 circRNAs with potential miRNA binding sites suggesting their role in post-transcriptional regulation of the genes. Finally, we confirmed the back-splicing sites of 9 randomly selected circRNAS using divergent primers and Sanger sequencing. Our study presents the first systematic analysis of circular RNAs during pollen development and forms the basis of future studies for unlocking complex gene regulatory networks underpinning reproduction in flowering plants.

2021 ◽  
Vol 22 (19) ◽  
pp. 10297
Author(s):  
Saeid Babaei ◽  
Mohan B. Singh ◽  
Prem L. Bhalla

Circular RNAs (circRNAs) are covalently closed RNA molecules generated by the back-splicing of exons from linear precursor mRNAs. Though various linear RNAs have been shown to play important regulatory roles in many biological and developmental processes, little is known about the role of their circular counterparts. In this study, we performed high-throughput RNA sequencing to delineate the expression profile and potential function of circRNAs during the five stages of pollen development in Brassica rapa. A total of 1180 circRNAs were detected in pollen development, of which 367 showed stage-specific expression patterns. Functional enrichment and metabolic pathway analysis showed that the parent genes of circRNAs were mainly involved in pollen-related molecular and biological processes such as mitotic and meiotic cell division, DNA processes, protein synthesis, protein modification, and polysaccharide biosynthesis. Moreover, by predicting the circRNA–miRNA network from our differentially expressed circRNAs, we found 88 circRNAs with potential miRNA binding sites, suggesting their role in post-transcriptional regulation of the genes. Finally, we confirmed the back-splicing sites of nine selected circRNAs using divergent primers and Sanger sequencing. Our study presents the systematic analysis of circular RNAs during pollen development and forms the basis of future studies for unlocking complex gene regulatory networks underpinning reproduction in flowering plants.


2020 ◽  
Author(s):  
Alexander Calderwood ◽  
Jo Hepworth ◽  
Shannon Woodhouse ◽  
Lorelei Bilham ◽  
D. Marc Jones ◽  
...  

AbstractThe timing of the floral transition affects reproduction and yield, however its regulation in crops remains poorly understood. Here, we use RNA-Seq to determine and compare gene expression dynamics through the floral transition in the model species Arabidopsis thaliana and the closely related crop Brassica rapa. A direct comparison of gene expression over time between species shows little similarity, which could lead to the inference that different gene regulatory networks are at play. However, these differences can be largely resolved by synchronisation, through curve registration, of gene expression profiles. We find that different registration functions are required for different genes, indicating that there is no common ‘developmental time’ to which Arabidopsis and B. rapa can be mapped through gene expression. Instead, the expression patterns of different genes progress at different rates. We find that co-regulated genes show similar changes in synchronisation between species, suggesting that similar gene regulatory sub-network structures may be active with different wiring between them. A detailed comparison of the regulation of the floral transition between Arabidopsis and B. rapa, and between two B. rapa accessions reveals different modes of regulation of the key floral integrator SOC1, and that the floral transition in the B. rapa accessions is triggered by different pathways, even when grown under the same environmental conditions. Our study adds to the mechanistic understanding of the regulatory network of flowering time in rapid cycling B. rapa under long days and highlights the importance of registration methods for the comparison of developmental gene expression data.


2021 ◽  
Vol 8 ◽  
Author(s):  
Jianwen Yu ◽  
Danli Xie ◽  
Naya Huang ◽  
Qin Zhou

Circular RNAs (circRNAs) are a novel type of non-coding RNAs that have aroused growing attention in this decade. They are widely expressed in eukaryotes and generally have high stability owing to their special closed-loop structure. Many circRNAs are abundant, evolutionarily conserved, and exhibit cell-type-specific and tissue-specific expression patterns. Mounting evidence suggests that circRNAs have regulatory potency for gene expression by acting as microRNA sponges, interacting with proteins, regulating transcription, or directly undergoing translation. Dysregulated expression of circRNAs were found in many pathological conditions and contribute to the pathogenesis and progression of various disorders, including renal diseases. Recent studies have revealed that circRNAs may serve as novel reliable biomarkers for the diagnosis and prognosis prediction of multiple kidney diseases, such as renal cell carcinoma (RCC), acute kidney injury (AKI), diabetic kidney disease (DKD), and other glomerular diseases. Furthermore, circRNAs expressed by intrinsic kidney cells are shown to play a substantial role in kidney injury, mostly reported in DKD and RCC. Herein, we review the biogenesis and biological functions of circRNAs, and summarize their roles as promising biomarkers and therapeutic targets in common kidney diseases.


2000 ◽  
Vol 28 (6) ◽  
pp. 567-574 ◽  
Author(s):  
J. Ohlrogge ◽  
M. Pollard ◽  
X. Bao ◽  
M. Focke ◽  
T. Girke ◽  
...  

For over 25 years there has been uncertainty over the pathway from CO2, to acetyl-CoA in chloroplasts. On the one hand, free acetate is the most effective substrate for fatty acid synthesis by isolated chloroplasts, and free acetate concentrations reported in leaf tissue (0.1–1 mM) appear adequate to saturate fatty acid synthase. On the other hand, a clear mechanism to generate sufficient free acetate for fatty acid synthesis is not established and direct production of acetyl-CoA from pyruvate by a plastid pyruvate dehydrogenase seems a more simple and direct path. We have re-examined this question and attempted to distinguish between the alternatives. The kinetics of 13CO2 and 14CO2 movement into fatty acids and the absolute rate of fatty acid synthesis in leaves was determined in light and dark. Because administered 14C appears in fatty acids within < 2–3 min our results are inconsistent with a large pool of free acetate as an intermediate in leaf fatty acid synthesis. In addition, these studies provide an estimate of the turnover rate of fatty acid in leaves. Studies similar to the above are more complex in seeds, and some questions about the regulation of plant lipid metabolism seem difficult to solve using conventional biochemical or molecular approaches. For example, we have little understanding of why or how some seeds produce >50%, oil whereas other seeds store largely carbohydrate or protein. Major control over complex plant biochemical pathways may only become possible by understanding regulatory networks which provide ‘global’ control over these pathways. To begin to discover such networks and provide a broad analysis of gene expression in developing oilseeds, we have produced micro-arrays that display approx. 5000 seed-expressed Arabidopsis genes. Sensitivity of the arrays was 1–2 copies of mRNA/cell. The arrays have been hybridized with probes derived from seeds, leaves and roots, and analysis of expression ratios between the different tissues has allowed the tissue-specific expression patterns of many hundreds of genes to be described for the first time. Approx. 10% of the genes were expressed at ratios ≥ 10-fold higher in seeds than in leaves or roots. Included in this list are a large number of proteins of unknown function, and potential regulatory factors such as protein kinases, phosphatases and transcription factors. The arrays were also found to be useful for analysis of Brassica seeds.


2020 ◽  
Vol 38 (4_suppl) ◽  
pp. 230-230
Author(s):  
Manuel Valladares-Ayerbes ◽  
Carmen Garrigos ◽  
Miquel Taron ◽  
Angélica Figueroa ◽  
Enrique Aranda

230 Background: Circular RNAs (circRNAs) are emerging as essential regulators of cancer- related biological hallmarks, as cell proliferation, apoptosis, differentiation, immune regulation and angiogenesis. CircRNAs are abundant, conserved, and have a tissue‐specific expression pattern. These characteristics make them candidate to serve as biomarkers in liquid biopsy (LB) in cancer. The aim of this study is to analyse differential expression of circRNAs in the colorectal cancer (CRC) scenario. Methods: To comprehensively understand the expression patterns of circRNAs we characterized 13,617 circRNAs using a microarray [Arraystar v2 (8x15K)] in 10 human samples, five CRC cell lines, one colorectal human tumour, one normal colon healthy control, vs. Peripheral Human Blood Leukocytes (2 pools) and Human Bone Marrow. Differentially expressed circRNAs were identified using fold change (FC) cut-off or through Volcano Plot filtering respectively. CircRNAs having FC ▪2 and P-values ▪ 0.05 were selected. CircRNA/microRNA interaction was predicted with target prediction software. Results: Hierarchical clustering showed distinguishable circRNA expression profiling among 10 samples. These data indicated that circRNAs have a different expression pattern in colorectal tissues compared with that in blood and bone marrow tissues. The microarray data showed 2329 circRNAs differentially expressed (FC > 2.0, P < 0.05). Among them, 964 circRNAs were upregulated and 1365 were downregulated in colon tissues compared with blood and bone marrow. Using a stringent criterion (FC > 10, P≤ 0.01 and false discovery rate [FDR] < 0.05) we have identified 30 circRNA upregulated in colorectal cancer versus non tumour samples. CircRNA/microRNA interaction prediction analysis showed that most upregulated circRNAs contain miRNA Binding Sites (MREs) for cancer-related miRNA, including among others, miR-17, miR-103, miR-let-7g. Conclusions: Microarray analysis was used to comprehensively identify dysregulated circRNAs in CRC. We identify novel circRNAs could be valuable as blood-based CRC biomarkers.


2019 ◽  
Author(s):  
Meili Zheng ◽  
Lei Zhao ◽  
Xinchun Yang

AbstractRecent studies have reported circular RNA (circRNA) expression profiles in various tissue types; specifically, a recent work showed a detailed circRNA expression landscape in the heart. However, circRNA expression profile in human epicardial adipose tissue (EAT) remains undefined. RNA-sequencing was carried out to compare circRNA expression patterns in EAT specimens from coronary artery disease (CAD) cases between the heart failure (HF) and non-HF groups. The top highly expressed EAT circRNAs corresponded to genes involved in cell proliferation and inflammatory response, including KIAA0182, RHOBTB3, HIPK3, UBXN7, PCMTD1, N4BP2L2, CFLAR, EPB41L2, FCHO2, FNDC3B and SPECC1. Among the 141 circRNAs substantially different between the HF and non-HF groups (P<0.05;fold change>2), hsa_circ_0005565 stood out, and was mostly associated with positive regulation of metabolic processes and insulin resistancein GO and KEGG pathway analyses, respectively. These data indicate EAT circRNAs contribute to the pathogenesis of metabolic disorders causing HF.


2021 ◽  
Author(s):  
Caicai Lin ◽  
Changhao Zhou ◽  
Zhongqian Liu ◽  
Xingfeng Li ◽  
Zhenqiao Song

Abstract Background: Long noncoding RNAs (lncRNAs), circular RNAs (circRNAs), and microRNAs (miRNAs) have been shown to play fundamental roles in plant development. However, the information of these noncoding RNAs (ncRNAs) in Salvia miltiorrhiza remains largely unexplored. In this study, the expression pattern of ncRNAs in six tissues from the same strain of S. miltiorrhiza was analyzed to study the biological function of ncRNAs on active ingredients synthesis.Methods: Analysis of tanshinone content differences of two root simples was carried out on high-performance liquid chromatography (HPLC). RNA sequencing, GO and KEGG enrichment analysis were applied to analyzing the targets of diferentially expressed ncRNAs in different organs.Results: A total of 6,929 lncRNAs, 6,239 circRNAs, and 360 miRNAs were identified. Forty-eight lncRNAs, 70 miRNAs, and 26 circRNAs expressed differentially between red and white root tissues with significantly different tanshinone content. GO and KEGG pathway analysis of target genes of differently expressed ncRNAs indicated that some target genes are involved in the synthesis pathway of terpene, including diterpene and sesquiterpene. We also found many target genes related to secondary metabolites, including 2-C-Methyl-d-erythritol 2,4-cyclodiphosphate Synthase (SmMCS) and several CYP450s. Furthermore, most target genes may be related to the resistance of pathogens, such as receptor kinases, disease-resistant proteins, and pentatricopeptide repeat-containing proteins. Conclusions: The present study exhibited the tissue-specific expression patterns of ncRNAs preliminarily in S. miltiorrhiza, which may reflect that the formation of white root or red root is related to regulation by ncRNAs. It would provide a basis for further research about the regulation mechanism in the tanshinone synthesis process.


2021 ◽  
Vol 12 ◽  
Author(s):  
Yang Deng ◽  
Yajuan Qin ◽  
Pan Yang ◽  
Jianjun Du ◽  
Zheng Kuang ◽  
...  

MicroRNA (miRNA) is an important endogenous post-transcriptional regulator, while lettuce (Lactuca sativa) is a leafy vegetable of global economic significance. However, there are few studies on miRNAs in lettuce, and research on miRNA regulatory network in lettuce is absent. In this study, through deep sequencing of small RNAs in different tissues, together with a reference genome, 157 high-confidence miRNA loci in lettuce were comprehensively identified, and their expression patterns were determined. Using a combination of computational prediction and high-throughput experimental verification, a set of reliable lettuce miRNA targets were obtained. Furthermore, through RNA-Seq, the expression profiles of these targets and a comprehensive view of the negative regulatory relationship between miRNAs and their targets was acquired based on a correlation analysis. To further understand miRNA functions, a miRNA regulatory network was constructed, with miRNAs at the core and combining transcription factors and miRNA target genes. This regulatory network, mainly composed of feed forward loop motifs, greatly increases understanding of the potential functions of miRNAs, and many unknown potential regulatory links were discovered. Finally, considering its specific expression pattern, Lsa-MIR408 as a hub gene was employed to illustrate the function of the regulatory network, and genetic experiments revealed its ability to increase the fresh weight and achene size of lettuce. In short, this work lays a solid foundation for the study of miRNA functions and regulatory networks in lettuce.


2022 ◽  
Vol 23 (2) ◽  
pp. 650
Author(s):  
Laís Reis-das-Mercês ◽  
Tatiana Vinasco-Sandoval ◽  
Rafael Pompeu ◽  
Aline Cruz Ramos ◽  
Ana K. M. Anaissi ◽  
...  

Gastric cancer (GC) is the fifth most common type of cancer and the third leading cause of cancer death in the world. It is a disease that encompasses a variety of molecular alterations, including in non-coding RNAs such as circular RNAs (circRNAs). In the present study, we investigated hsa_circ_0000211, hsa_circ_0000284, hsa_circ_0000524, hsa_circ_0001136 and hsa_circ_0004771 expression profiles using RT-qPCR in 71 gastric tissue samples from GC patients (tumor and tumor-adjacent samples) and volunteers without cancer. In order to investigate the suitability of circRNAs as minimally invasive biomarkers, we also evaluated their expression profile through RT-qPCR in peripheral blood samples from patients with and without GC (n = 41). We also investigated the predicted interactions between circRNA-miRNA-mRNA and circRNA-RBP using the KEGG and Reactome databases. Overall, our results showed that hsa_circ_0000211, hsa_circ_0000284 and hsa_circ_0004771 presented equivalent expression profiles when analyzed by different methods (RNA-Seq and RT-qPCR) and different types of samples (tissue and blood). Further, functional enrichment results identified important signaling pathways related to GC. Thus, our data support the consideration of circRNAs as new, minimally invasive biomarkers capable of aiding in the diagnosis of GC and with great potential to be applied in clinical practice.


2017 ◽  
Vol 69 (3) ◽  
pp. 523-534 ◽  
Author(s):  
Xi Wang ◽  
Yong Dai ◽  
Wanfan Zhang ◽  
S SunDonglin ◽  
Xinzhou Zhang

Circular RNAs (circRNAs) have been identified in many diseases and shown to play important roles in pathological processes. The expression patterns of circRNA in uremia remains unknown. The aim of this study was to screen circRNA in plasma and peripheral blood mononuclear cells (PBMCs)in healthy controls and patients with uremia due to chronic glomerulonephritis, and to provide evidence for further exploration of the pathogenesis, diagnosis and treatment of uremic patients. Twenty individuals were included in this study, of which 10 were healthy and 10 were patients with uremia caused by chronic glomerulonephritis without systemic lupus erythematosus(SLE). Peripheral blood was collected from each individual in the two groups and the PBMCs were separated. The circRNAs expression profile was examined using a human circRNA microarray. The expression of differently expressed circRNAs was further validated by qRT-PCR. Seven hundred ten circRNAs were differentially expressed in the plasma in the two groups, accounting for 27.58% of the total circRNA(710/2578). Three hundred eighty-five up regulated circRNAs accounted for 14.93% and 325 down regulated circRNAs accounted for 12.60% of the total circRNAs. Additionally, 968 circRNAs were differentially expressed in PBMCs in the two groups, accounting for 29.24% of all circRNAs (968/3310).Six hundred seventy upregulated circRNAs accounted for 20.24% and 298 down regulated circRNAs accounted for 9.00% of the total circRNAs. The results of qRT-PCR validation were consistent with the microarray gene expression results. The expression profile of circRNAs was altered in the plasma and PBMCs of patients with uremia, which suggests that the changed circRNAs may be potential diagnostic biomarkers that play an important role in the pathogenesis of uremic patients. We speculate that hsa_circ_0053958, hsa_circ_0103281 may be associated with the pathogenesis of uremia and may be potential biological molecular markers for the diagnosis and prognosis of uremia.


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