Hermaphroditic freshwater mussel Anodonta cygnea does not have supranumerary open reading frames in the mitogenome.
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ABSTRACT:
SUBMITTER: Soroka M
PROVIDER: S-EPMC7800200 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BackgroundDoubly uniparental inheritance (DUI) of mitochondrial DNA in bivalves is a fascinating exception to strictly maternal inheritance as practiced by all other animals. Recent work on DUI suggests that there may be unique regions of the mitochondrial genomes that play a role in sex determination and/or sexual development in freshwater mussels (order Unionoida). In this study, one complete mitochondrial genome of the hermaphroditic swan mussel, Anodonta cygnea, is sequenced and compared to the complete mitochondrial genome of the gonochoric duck mussel, Anodonta anatina. An in silico assessment of novel proteins found within freshwater bivalve species (known as F-, H-, and M-open reading frames or ORFs) is conducted, with special attention to putative transmembrane domains (TMs), signal peptides (SPs), signal cleavage sites (SCS), subcellular localization, and potential control regions. Characteristics of TMs are also examined across freshwater mussel lineages.ResultsIn silico analyses suggests the presence of SPs and SCSs and provides some insight into possible function(s) of these novel ORFs. The assessed confidence in these structures and functions was highly variable, possibly due to the novelty of these proteins. The number and topology of putative TMs appear to be maintained among both F- and H-ORFs, however, this is not the case for M-ORFs. There does not appear to be a typical control region in H-type mitochondrial DNA, especially given the loss of tandem repeats in unassigned regions when compared to F-type mtDNA.ConclusionIn silico analyses provides a useful tool to discover patterns in DUI and to navigate further in situ analyses related to DUI in freshwater mussels. In situ analysis will be necessary to further explore the intracellular localizations and possible role of these open reading frames in the process of sex determination in freshwater mussel.
| S-EPMC5870820 | biostudies-literature
Project description:Ribosome profiling has revealed pervasive but largely uncharacterized translation outside of canonical coding sequences (CDSs). Here, we exploit a systematic CRISPR-based screening strategy to identify hundreds of non-canonical CDSs that are essential for cellular growth and whose disruption elicit specific, robust transcriptomic and phenotypic changes in human cells. Functional characterization of the encoded microproteins reveals distinct cellular localizations, specific protein binding partners, and hundreds that are presented by the HLA system. Interestingly, we find multiple microproteins encoded in upstream open reading frames, which form stable complexes with the main, canonical protein encoded on the same mRNA, thus revealing the diverse use of functional bicistronic operons in mammals. Together, our results point to a family of functional human microproteins that play critical and diverse cellular roles.
2020-03-14 | GSE131650 | GEO
Project description:Using a new fossil-calibrated mitogenome-based approach, we identified macroevolutionary shifts in mitochondrial gene order among the freshwater mussels (Unionoidea). We show that the early Mesozoic divergence of the two Unionoidea clades, Margaritiferidae and Unionidae, was accompanied by a synchronous split in the gene arrangement in the female mitogenome (i.e., gene orders MF1 and UF1). Our results suggest that this macroevolutionary jump was completed within a relatively short time interval (95% HPD 201-226 Ma) that coincided with the Triassic-Jurassic mass extinction. Both gene orders have persisted within these clades for ~200 Ma. The monophyly of the so-called "problematic" Gonideinae taxa was supported by all the inferred phylogenies in this study using, for the first time, the M- and F-type mitogenomes either singly or combined. Within Gonideinae, two additional splits in the gene order (UF1 to UF2, UF2 to UF3) occurred in the Mesozoic and have persisted for ~150 and ~100 Ma, respectively. Finally, the mitogenomic results suggest ancient connections between freshwater basins of East Asia and Europe near the Cretaceous-Paleogene boundary, probably via a continuous paleo-river system or along the Tethys coastal line, which are well supported by at least three independent but almost synchronous divergence events.
| S-EPMC6906506 | biostudies-literature
Project description:Using a selection of molecular biomarkers, we evaluated responses in freshwater mussels (Anodonta anatina) exposed to effluent from an industrial wastewater treatment facility. The aims of this work were to (1) assess biomarkers of general toxicity under sublethal exposure to an anthropogenic mixture of chemicals, represented by an arbitrary effluent, and (2) evaluate the potential of A. anatina as a bioindicator of pollution. Adult mussels (n = in total 32; 24 males and 8 females) were exposed (96 h) in the laboratory to a fixed dilution of effluent or to a control treatment of standardized freshwater. Metal concentrations were in general higher in the effluent, by an order of magnitude or more, compared to the control. Toxic unit estimates were used as proxies of chemical stress, and Cu, Ni, and Zn were identified as potential major contributors (Cu> Ni > Zn). Six transcriptional (cat, gst, hsp70, hsp90, mt, sod) and two biochemical (AChE, GST) biomarkers were analyzed in two tissues, gills, and digestive glands. Out of the 16 responses (eight biomarkers × two tissues), 14 effect sizes were small (within ± 28 % of control) and differences non-significant (p > 0.05). Results did however show that (1) AChE activity increased by 40% in gills of exposed mussels compared to control, (2) hsp90 expression was 100% higher in exposed female gills compared to control, and (3) three marker signals (AChE in both tissues, and hsp70 in gills) differed between sexes, independent of treatment. Results highlight a need for further investigation of molecular biomarker variability and robustness in A. anatina.
| S-EPMC8732836 | biostudies-literature
Project description:Open reading frames (ORFs) are the genomic DNA sequences that have the potential to be translated. Genome annotation pipelines dismiss translation products of small ORFs (smORFs) of less than 100 codons (<300 nucleotides) as being unlikely to have a biological function. In this study, we systematically characterized smORFs in mouse B and T cells under different conditions and predicted a total of 5744 unique actively translated smORFs. We then extended our analysis to ORFs of 101-200 codons in length and predicted 945 of such longer translation products. Additionally, our results have suggested the existence of candidate secreted micropeptides. Furthermore, verifying their existence and identifying their functions will be essential and potentially lead to useful applications.
2021-04-28 | GSE154491 | GEO
Project description:Gene expression is prone to burst production, making it a highly noisy process that requires additional controls. Upstream open reading frames (uORFs) are widely present in the 5' leader sequences of 30-50% of eukaryotic messenger RNAs1-3. The translation of uORFs can repress the translation efficiency of the downstream main coding sequences. Whether the low translation efficiency leads to a different variation, or noise, in gene expression has not been investigated, nor has the direct biological impact of uORF-repressed translation. Here we show that uORFs achieve low but precise protein production in plant cells, possibly by reducing the protein production rate. We also demonstrate that, by buffering a stable TIMING OF CAB EXPRESSION 1 (TOC1) protein production level, uORFs contribute to the robust operation of the plant circadian clock. Our results provide both an action model and the biological impact of uORFs in translational control to mitigate transcriptional noise for precise protein production.
| S-EPMC9122824 | biostudies-literature
Project description: Not available
| S-EPMC9757701 | biostudies-literature
Project description:Molecular biomarkers, like gene transcripts or enzyme activities, are potentially powerful tools for early warning assessment of pollution. However, a thorough understanding of response and baseline variation is required to distinguish actual effects from pollution. Here, we assess the freshwater mussel Anodonta anatina as a biomarker model species for freshwater ecosystems, by testing responses of six transcriptional (cat, gst, hsp70, hsp90, mt, and sod) and two biochemical (AChE and GST) biomarkers to environmentally relevant Cu water concentrations. Mussels (n = 20), collected from a stream free from point source pollution, were exposed in the laboratory, for 96 h, to Cu treatments (< 0.2 μg/L, 0.77 ± 0.87 μg/L, and 6.3 ± 5.4 μg/L). Gills and digestive glands were extracted and analyzed for transcriptional and biochemical responses. Biological and statistical effect sizes from Cu treatments were in general small (mean log2 fold-change ≤ 0.80 and Cohen's f ≤ 0.69, respectively), and no significant treatment effects were observed. In contrast, four out of eight biomarkers (cat, gst, hsp70, and GST) showed a significant sex:tissue interaction, and additionally one (sod) showed significant overall effects from sex. Specifically, three markers in gills (cat, mt, GST) and one in digestive gland (AChE) displayed significant sex differences, independent of treatment. Results suggest that sex or tissue effects might obscure low-magnitude biomarker responses and potential early warnings. Thus, variation in biomarker baselines and response patterns needs to be further addressed for the future use of A. anatina as a biomarker model species.
| S-EPMC7089896 | biostudies-literature
Project description:Protein-coding small open reading frames (smORFs) are emerging as an important class of genes, however, the coding capacity of smORFs in the human genome is unclear. By integrating de novo transcriptome assembly and Ribo-Seq, we confidently annotate thousands of novel translated smORFs in three human cell lines. We find that smORF translation prediction is noisier than for annotated coding sequences, underscoring the importance of analyzing multiple experiments and footprinting conditions. These smORFs are located within non-coding and antisense transcripts, the UTRs of mRNAs, and unannotated transcripts. Analysis of RNA levels and translation efficiency during cellular stress identifies regulated smORFs and provides an approach for identifying smORFs for further investigation. Sequence conservation and signatures of positive selection indicate that encoded microproteins are likely functional. Additionally, proteomics data from enriched human leukocyte antigen complexes validates the translation of hundreds of smORFs and positions them as a source of novel antigens. Thus, smORFs represent a significant number of important, yet unexplored human genes.
2019-07-03 | GSE125218 | GEO
Project description:BackgroundUpstream open reading frames (uORFs) can down-regulate the translation of the main open reading frame (mORF) through two broad mechanisms: ribosomal stalling and reducing reinitiation efficiency. In distantly related plants, such as rice and Arabidopsis, it has been found that conserved uORFs are rare in these transcriptomes with approximately 100 loci. It is unclear how prevalent conserved uORFs are in closely related plants.ResultsWe used a homology-based approach to identify conserved uORFs in five cereals (monocots) that could potentially regulate translation. Our approach used a modified reciprocal best hit method to identify putative orthologous sequences that were then analysed by a comparative R-nomics program called uORFSCAN to find conserved uORFs.ConclusionThis research identified new genes that may be controlled at the level of translation by conserved uORFs. We report that conserved uORFs are rare (<150 loci contain them) in cereal transcriptomes, are generally short (less than 100 nt), highly conserved (50% median amino acid sequence similarity), position independent in their 5'-UTRs, and their start codon context and the usage of rare codons for translation does not appear to be important.
| S-EPMC2527020 | biostudies-literature