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At least 73 records · Page 4Linked to original sources

Analysis of a new homozygous deletion in the tumor suppressor region at 3p12.3 reveals two novel intronic noncoding RNA genes.

Homozygous deletions or loss of heterozygosity (LOH) at human chromosome band 3p12 are consistent features of lung and other malignancies, suggesting the presence of a tumor suppressor gene(s) (TSG) at this location. Only one gene has been cloned thus far from the overlapping region deleted in lung and breast cancer cell lines U2020, NCI H2198, and HCC38. It is DUTT1 (Deleted in U Twenty Twenty), also known as ROBO1, FLJ21882, and SAX3, according to HUGO. DUTT1, the human ortholog of the fly gene ROBO, has homology with NCAM proteins. Extensive analyses of DUTT1 in lung cancer have not revealed any mutations, suggesting that another gene(s) at this location could be of importance in lung cancer initiation and progression. Here, we report the discovery of a new, small, homozygous deletion in the small cell lung cancer (SCLC) cell line GLC20, nested in the overlapping, critical region. The deletion was delineated using several polymorphic markers and three overlapping P1 phage clones. Fiber-FISH experiments revealed the deletion was approximately 130 kb. Comparative genomic sequence analysis uncovered short sequence elements highly conserved among mammalian genomes and the chicken genome. The discovery of two EST clusters within the deleted region led to the isolation of two noncoding RNA (ncRNA) genes. These were subsequently found differentially expressed in various tumors when compared to their normal tissues. The ncRNA and other highly conserved sequence elements in the deleted region may represent miRNA targets of importance in cancer initiation or progression.

Animals↗

Genome-Wide Identification and Characterization of Thaumatin-Like Proteins in Potato (Solanum tuberosum L.) and Their Role in Stress Tolerance.

Thaumatin-like proteins (TLPs), part of the Pathogenesis-related protein 5 (PR5) family, play key roles in plant defense against biotic and abiotic stresses. In Solanum tuberosum, a crucial global food crop, the functional diversity of TLPs under stress conditions remains poorly understood, hindering efforts to improve stress tolerance. This study aimed to address this gap by performing a genome-wide identification and characterization of the TLP gene family in potato. We identified 34 TLPs (StTLP1 to StTLP34), distributed across 11 chromosomes. Detailed analyses were conducted on their physicochemical properties, gene structures, conserved motifs, and expression patterns. Promoter analysis revealed multiple stress-responsive cis-elements. Differential expression analysis showed that several StTLPs are significantly regulated in response to salinity, heat, and pathogen infection. Protein-protein interaction and miRNA targeting analyses further highlighted the regulatory networks involving StTLPs in stress adaptation. This study advances the theoretical understanding of the roles of StTLPs in stress response. It provides a valuable genetic resource for future efforts to enhance stress resilience in potato, with potential applications in crop improvement strategies. The 0 l expression of three TLP genes under salt and mannitol stress was verified through real-time PCR analysis after the interval of 15 days. Alterations in the expression patterns of StTLPs offered deeper insight into the involvement of this gene family in diverse abiotic stress responses. All three StTLPs were upregulated under both treatments at 400 mM, relative to their expression at 200 mM. The highest level of upregulation was observed in StTLP20, indicating its prominent role in both stress treatments.

Solanum tuberosum↗

A two-hit trigger for siRNA biogenesis in plants.

In Arabidopsis, microRNA-directed cleavage can define one end of RNAs that then generate phased siRNAs. However, most miRNA-targeted RNAs do not spawn siRNAs, suggesting the existence of additional determinants within those that do. We find that in moss, phased siRNAs arise from regions flanked by dual miR390 cleavage sites. AtTAS3, an siRNA locus important for development and conserved among higher plants, also has dual miR390 complementary sites. Both sites bind miR390 in vitro and are functionally required in Arabidopsis, but cleavage is undetectable at the 5' site--demonstrating that noncleavable sites can be functional in plants. Phased siRNAs also emanate from the bounded regions of every Arabidopsis gene with two known microRNA/siRNA complementary sites, but only rarely from genes with single sites. Therefore, two "hits,"--often, but not always, two cleavage events--constitute a conserved trigger for siRNA biogenesis, a finding with implications for recognition and silencing of aberrant RNA.

Arabidopsis↗

Stage-specific expression of microRNAs during Xenopus development.

MicroRNAs (miRNAs) repress target genes at the post-transcriptional level and play important roles in development and cell lineage decision. However, in vertebrates, both the targets of miRNAs and their expression profile during development are poorly understood. Here, we report the detailed expression profiles of miRNAs from oocyte stage to tadpole stage in Xenopus laevis. As development proceeds, a variety of miRNAs start to be expressed. Most miRNAs emerged at a specific stage and were continuously expressed until the tadpole stage. In addition, we identified a novel miRNA that was expressed only at specific stages of development and that is likely to have roles in midblastula transition.

Animals↗

The pleiotropic Arabidopsis frd mutation with altered coordination of chloroplast biogenesis, cell size and differentiation, organ size and number.

In higher plants, plastid development must be tightly coordinated with cell and organ development. In this paper, a novel T-DNA-mutagenized Arabidopsis line showing chlorotic leaves and minute stature was identified in a genetic screen for altered chloroplast development. The mutation corresponded to a single locus on chromosome IV and was associated with insertion of the T-DNA. This locus was named FARFADET and resulted in pleiotropic effects on chloroplast biogenesis, cell size and differentiation, organ size and number. Thus, in contrast with previously described chlorotic mutants, frd mutants were affected not only in chloroplast development and chlorophyll accumulation, but also in cell and organ development. Alteration of differentiation affected different cell types such as leaf epidermal cells, trichomes, mesophyll cells, and columella cells. A major effect on mesophyll cell differentiation was the lack of palisadic parenchyma and absence of grana stacks. Moreover, meristem size and lateral meristem initiation were affected. Genetic and molecular characterisation showed that the T-DNA insertion generated 41 bp deletion in a potential miRNA precursor. The predicted miRNA target genes were involved in plant development and stress. It is therefore hypothesized that the frd mutation had affected coordination of cell developmental span and the control of the division-differentiation balance.

Arabidopsis↗

Beyond Mfold: recent advances in RNA bioinformatics.

Computational analysis of RNA secondary structure is a classical field of biosequence analysis, which has recently gained momentum due to the manyfold regulatory functions of RNA that have become apparent. We present five recent computational approaches that address the problems of synoptic folding space analysis, pseudoknot prediction, structure alignment, comparative structure prediction, and miRNA target prediction. All these programs are in current use and are available via the Bielefeld Bioinformatics Server at .

Animals↗

HIV may produce inhibitory microRNAs (miRNAs) that block production of CD28, CD4 and some interleukins.

It is well-known that HIV-1 infection results in a gradual decline of the CD4+ T-lymphocytes, but the underlying mechanism of this decline is not completely understood. Research has shown that HIV-1 infection of CD4+ T cells results in decreased CD28 expression, but the mechanism of this repression is unknown. There is also substantial evidence demonstrating regulatory involvement of microRNA (miRNA) during protein expression in plants and some animals, and reports have recently been published confirming the existence of viral-encoded miRNAs. Based on these findings, we hypothesize that viral-encoded miRNA from HIV-1 may directly alter T cell, macrophage and dendritic cell activity. To investigate a potential correlation between the genomic complementarity of HIV-1 and host cell protein expression, a local alignment search was performed to assess for regions of complementarity between the HIV-1 proviral genome and the mRNA coding sequence of various proteins expressed by CD+ T cells and macrophages. Regions of complementarity with strong correlations to the currently established criteria for miRNA:target mRNA activity were found between HIV-1 and CD28, CTLA-4 and some interleukins, suggesting that HIV-1 may produce translational repression in host cells.

Base Sequence↗

T cell lineage choice and differentiation in the absence of the RNase III enzyme Dicer.

The ribonuclease III enzyme Dicer is essential for the processing of micro-RNAs (miRNAs) and small interfering RNAs (siRNAs) from double-stranded RNA precursors. miRNAs and siRNAs regulate chromatin structure, gene transcription, mRNA stability, and translation in a wide range of organisms. To provide a model system to explore the role of Dicer-generated RNAs in the differentiation of mammalian cells in vivo, we have generated a conditional Dicer allele. Deletion of Dicer at an early stage of T cell development compromised the survival of alphabeta lineage cells, whereas the numbers of gammadelta-expressing thymocytes were not affected. In developing thymocytes, Dicer was not required for the maintenance of transcriptional silencing at pericentromeric satellite sequences (constitutive heterochromatin), the maintenance of DNA methylation and X chromosome inactivation in female cells (facultative heterochromatin), and the stable shutdown of a developmentally regulated gene (developmentally regulated gene silencing). Most remarkably, given that one third of mammalian mRNAs are putative miRNA targets, Dicer seems to be dispensable for CD4/8 lineage commitment, a process in which epigenetic regulation of lineage choice has been well documented. Thus, although Dicer seems to be critical for the development of the early embryo, it may have limited impact on the implementation of some lineage-specific gene expression programs.

Animals↗

GUUGle: a utility for fast exact matching under RNA complementary rules including G-U base pairing.

MOTIVATION: RNA secondary structure analysis often requires searching for potential helices in large sequence data. RESULTS: We present a utility program GUUGle that efficiently locates potential helical regions under RNA base pairing rules, which include Watson-Crick as well as G-U pairs. It accepts a positive and a negative set of sequences, and determines all exact matches under RNA rules between positive and negative sequences that exceed a specified length. The GUUGle algorithm can also be adapted to use a precomputed suffix array of the positive sequence set. We show how this program can be effectively used as a filter preceding a more computationally expensive task such as miRNA target prediction. AVAILABILITY: GUUGle is available via the Bielefeld Bioinformatics Server at http://bibiserv.techfak.uni-bielefeld.de/guugle

Algorithms↗

RegRNA: an integrated web server for identifying regulatory RNA motifs and elements.

Numerous regulatory structural motifs have been identified as playing essential roles in transcriptional and post-transcriptional regulation of gene expression. RegRNA is an integrated web server for identifying the homologs of regulatory RNA motifs and elements against an input mRNA sequence. Both sequence homologs and structural homologs of regulatory RNA motifs can be recognized. The regulatory RNA motifs supported in RegRNA are categorized into several classes: (i) motifs in mRNA 5'-untranslated region (5'-UTR) and 3'-UTR; (ii) motifs involved in mRNA splicing; (iii) motifs involved in transcriptional regulation; (iv) riboswitches; (v) splicing donor/acceptor sites; (vi) inverted repeats; and (vii) miRNA target sites. The experimentally validated regulatory RNA motifs are extracted from literature survey and several regulatory RNA motif databases, such as UTRdb, TRANSFAC, alternative splicing database (ASD) and miRBase. A variety of computational programs are integrated for identifying the homologs of the regulatory RNA motifs. An intuitive user interface is designed to facilitate the comprehensive annotation of user-submitted mRNA sequences. The RegRNA web server is now available at http://RegRNA.mbc.NCTU.edu.tw/.

Animals↗

The MIR169:NF-YA module enhances biomass and yield via ARGOS in Arabidopsis and tomato.

Molecular links between miRNA: target modules regulating downstream genes for crop maturation/yield are poorly understood. Here, we report that elevated miR169d expression and concomitant reduced NF-YA2 (Nuclear Factor-Y subunit-A) target levels positively regulate vegetative growth and yield in Arabidopsis along with a shorter life cycle. In agreement, increased NF-YA2 levels in (1) NF-YA2-OE (overexpression) lines, (2) miR169d-target-mimicry lines (in which miR169d is chelated), and (3) miR169d-non-cleavable NF-YA2 resistant target lines show the opposite phenotype. Further, we find increased auxin levels in MIR169d-OE and nf-ya2 mutant lines, supporting the enrichment of 'auxin terms' in MIR169-OE transcriptome data. We show that ARGOS (auxin-regulated gene involved in organ size) is upregulated in MIR169d-OE due to reduced NF-YA2 repressor levels and that NF-YA2 directly binds the ARGOS promoter. Genetic screens of this module show that neither overexpressing miR169d in an argos mutant background nor the nf-ya2:argos double mutants rescue the argos mutant phenotype, suggesting a parallel pathway of ARGOS regulation via the MIR169:NF-YA2 node, independent of auxin. To assess the translational potential of this module in a crop, we show that Sly-MIR169-OE lines in tomato, having reduced target Sly-NF-YA10 levels, also regulate Sly-ARGOS resulting in early flowering, larger sized fruits, more fruit fresh weight, higher fruit set, early fruiting, and better shelf life than wild-type plants. In contrast, Sly-STTM169 plants inhibited for Sly-miR169 action and having increased levels of Sly-NF-YA10 have a longer life cycle with reduced biomass, decreased fruit set, and an overall reduction in yield. Thus, our findings show a conserved MIR169:NF-YA:ARGOS module which can be applied to crops for addressing future food demands.

MicroRNAs↗

New porcine microRNA genes found by homology search.

MicroRNAs (miRNAs) repress target genes at the post-transcriptional level and play important roles in development and cell lineage decisions. In vertebrates, however, both the targets of miRNAs and their expression profiles during development are poorly understood. Thus far, 326 human miRNAs, 249 mouse miRNAs, and 195 rat miRNAs have been identified. Even though the pig is a promising animal model in regenerative biology, as well as in livestock production, only 54 pig miRNAs have been identified. Here, we report the identification of 58 new pig miRNAs. We conducted a homology search using either human or mouse miRNAs genes queried against the pig genome. The new pig miRNAs consist of 23 miRNAs showing homology to mouse, 21 showing homology to human, and 16 showing homology to both human and mouse. The expression profile of 6 miRNAs were analyzed by Northern blot analysis isolated from porcine tissues: ovary, heart, kidney, liver, and pancreas.

Animals↗

Genome-wide identification and expression analysis of the UGT gene family in honeysuckle.

BACKGROUND: The UGT gene family plays critical roles in regulating plant growth, development, stress responses, and secondary metabolite synthesis. Although UGT proteins have been studied in numerous plant species, research on the UGT family in honeysuckle (Lonicera japonica Thunb.) remains limited. RESULTS: In this study, a comprehensive genome-wide analysis of the UGT gene family was performed in honeysuckle. A total of 224 unique LjUGT genes were identified and classified into 21 distinct subfamilies (T71-T92 without T77) based on the phylogenetic analysis. These genes were unevenly distributed on the 9 chromosomes. Eighteen segmental duplication events and 61 tandem duplications were identified, of which only 3 were positive selection. Integrated analysis of promoter cis-acting elements, transcription factors, targeted miRNAs, and interacting proteins suggested that the expression and function of the LjUGT genes may be regulated by transcription factors and proteins through binding to the various binding sites and cis-acting elements, thereby putatively participating in diverse biological processes, including hormone signaling, stress response, and metabolism. The expression pattern analysis of LjUGTs in different tissues and under stress conditions indicated that Lj2A1135G32, Lj5A236T61, Lj6A350T83, and Lj7A737T47 emerged as candidate genes potentially associated with development, 46 genes showed expression changes under all 6 abiotic stresses, suggesting broad stress responsiveness. Additionally, there 7 genes were identified as candidate hub genes that may correlate with the low temperature stress tolerance in honeysuckle according to the WGCNA results, and further verification by qRT-PCR confirmed that Lj4A99G61 and Lj9A591T82 can be regarded as key candidate genes for in-depth research. CONCLUSIONS: This study systematically identified 224 LjUGT genes in honeysuckle for the first time and characterized their physicochemical properties, phylogenetic relationship, and expression patterns. These findings provide a foundational resource for hypothesis-driven investigations into the functions and action mechanisms of LjUGTs.

Lonicera↗

Identifying microRNA regulators of cell death in Drosophila.

Animal genomes contain on the order of at least hundreds of microRNAs (miRNAs). Although most remain uncharacterized, it is already clear that miRNAs regulate many biological processes. A number of Drosophila miRNAs have been identified as likely cell death regulators, but functions for most have simply not been explored. Here we describe a protocol for identifying miRNAs that can act as cell death regulators. We also describe a simple protocol for testing roles for mRNAs identified as candidate miRNA targets using computational or other approaches.

Animals↗

Novel serum small extracellular vesicle miRNAs with multi-target RCA-CRISPR sensor for liver cancer detection.

BACKGROUND: Detecting liver cancer (LC) remains a significant challenge in clinical practice. Small extracellular vesicle (sEV) miRNAs show promise as non-invasive biomarkers for LC detection, yet their diagnostic potential remains largely unexplored. This study aimed to identify specific sEV miRNA signatures for LC detection and develop a novel synchronized multi-miRNA detection platform to enhance diagnostic efficiency and sensitivity. METHODS: High-throughput sequencing was conducted across four distinct cohorts: normal controls (NC), hepatitis B virus (HBV) patients, liver cirrhosis patients, and LC patients. This sequencing process identified miRNAs with differential expression, followed by RT-qPCR validation in serum sEV miRNAs from LC patients and NC. An innovative detection method, RCA-CRISPR, was introduced, combining rolling circle amplification (RCA) with CRISPR/Cas12a (RCA-CRISPR) for quick and sensitive miRNAs detection. RESULTS: Sequencing results showed a consistent elevation of hsa-miR-203b-5p, hsa-miR-4661-5p, and hsa-miR-219a-2-3p across all cohorts. RT-qPCR validations confirmed significant upregulation of these miRNAs in serum sEVs from LC patients, and the combined three-miRNA panel exhibited high diagnostic accuracy (p = 0.0003; AUC = 0.81). The RCA-CRISPR method demonstrated a detection limit of 3.12 pM for simultaneous multi-target miRNA detection, highlighting its exceptional sensitivity. CONCLUSIONS: Our study identifies hsa-miR-203b-5p, hsa-miR-4661-5p, and hsa-miR-219a-2-3p as promising sEV miRNA biomarkers for LC detection. The developed RCA-CRISPR sensor provides a robust tool for multi-miRNA analysis, potentially advancing non-invasive LC diagnostics. Future validation in larger, prospectively collected cohorts is essential to establish the clinical utility and performance of this biomarker panel and RCA-CRISPR sensor.

MicroRNAs↗

A novel method to detect functional microRNA targets.

MicroRNA (miRNA) molecules are non-coding RNAs, 19 to 24 nt in length that have been identified recently as important regulators of gene expression. Several computational methods have been developed to describe the target recognition mechanism by miRNA. We propose here a novel method to detect miRNA-mRNA complexes in eukaryotic cells. As a first step, we synthesize cDNA on an mRNA template using miRNAs as the endogenous cytoplasmic primer. This step extends miRNA and overcomes the problem of low complementary binding of miRNAs to their targets. Purified hybrid 3'-cDNA-miRNA-5' molecules are used in a second round of reverse transcription to anneal to target mRNA in a highly gene-specific manner. The 5'-end analysis of these cDNA molecules demonstrated that primers for cDNAs were "signatures" of miRNA molecules, and over-expression of their full-length mature miRNAs resulted in functional inhibition of target protein expression.

Base Sequence↗

Prediction of mammalian microRNA targets.

MicroRNAs (miRNAs) can play important gene regulatory roles in nematodes, insects, and plants by basepairing to mRNAs to specify posttranscriptional repression of these messages. However, the mRNAs regulated by vertebrate miRNAs are all unknown. Here we predict more than 400 regulatory target genes for the conserved vertebrate miRNAs by identifying mRNAs with conserved pairing to the 5' region of the miRNA and evaluating the number and quality of these complementary sites. Rigorous tests using shuffled miRNA controls supported a majority of these predictions, with the fraction of false positives estimated at 31% for targets identified in human, mouse, and rat and 22% for targets identified in pufferfish as well as mammals. Eleven predicted targets (out of 15 tested) were supported experimentally using a HeLa cell reporter system. The predicted regulatory targets of mammalian miRNAs were enriched for genes involved in transcriptional regulation but also encompassed an unexpectedly broad range of other functions.

3' Untranslated Regions↗

Identification of 188 conserved maize microRNAs and their targets.

MicroRNAs (miRNAs) represent a newly identified class of non-protein-coding approximately 20nt small RNAs which play important roles in multiple biological processes by degrading targeted mRNAs or repressing mRNA translation. After searching a genomic survey sequence database using homologs and secondary structures, we found 188 maize miRNAs belonging to 29 miRNA families. Of the 188 maize miRNA genes, 28 (15%) were found in at least one EST. A total of 115 potential targets were identified for 26 of the miRNA families based on the fact that miRNAs exhibit perfect or nearly perfect complementarity with their target sequences. A majority of the targets are transcription factors which play important roles in maize development, including leaf, shoot, and root development. Additionally, these maize miRNAs are also involved in other cellular processes, such as signal transduction, stress response, sucrose and cellulose synthesis, and ubiquitin protein degradation pathway. Some of the newly identified miRNA targets may be unique to maize.

Base Sequence↗