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Updated: Jul 16, 2026
08:53
A Reporter Based Cellular Assay for Monitoring Splicing Efficiency
Published on: September 15, 2021
Spliced leader RNA trans-splicing in dinoflagellates
Huan Zhang1, Yubo Hou, Lilibeth Miranda
1Department of Marine Sciences, University of Connecticut, 1080 Shennecossett Road, Groton, CT 06340, USA.
Summary
Dinoflagellates universally use spliced leader (SL) trans-splicing for nuclear-encoded mRNAs, adding a conserved SL sequence to the 5' end. This process, unusual in its SL RNA structure and Sm binding site location, impacts mRNA translation and stability.
Area of Science:
- Molecular Biology
- Eukaryotic Gene Expression
- RNA Processing
Background:
- Spliced leader (SL) trans-splicing is a rare eukaryotic RNA processing event enabling polycistronic gene translation.
- Dinoflagellates, a diverse group of eukaryotes, exhibit unique characteristics in their gene expression machinery.
- Understanding RNA splicing mechanisms is crucial for deciphering gene regulation and protein synthesis.
Purpose of the Study:
- To investigate the prevalence and characteristics of SL trans-splicing in dinoflagellates across major lineages.
- To analyze the structure and potential function of SL RNAs and their associated motifs in dinoflagellates.
- To explore the implications of conserved SL trans-splicing for mRNA translation and stability in this group.
Main Methods:
- Analysis of hundreds of full-length cDNAs from fifteen diverse dinoflagellate species.
- Identification and characterization of conserved spliced leader (SL) sequences and SL RNAs.
- Comparative analysis of SL RNA structure, including Sm binding site location, across different dinoflagellate orders.
Main Results:
- Nuclear-encoded mRNAs in all fifteen dinoflagellate species analyzed undergo SL trans-splicing with a conserved 22-nt SL (DCCGUAGCCAUUUUGGCUCAAG).
- Dinoflagellate SL RNAs are unusually short (50-60 nt) with a conserved Sm binding motif located within the SL (exon) rather than the intron.
- The SL element is present in mRNAs for diverse proteins, including Sm-complex subunits, suggesting conserved function despite altered location.
Conclusions:
- SL trans-splicing is a universal and conserved mechanism in dinoflagellates, essential for mRNA maturation.
- The unique structure of dinoflagellate SL RNAs, particularly the exon-located Sm binding site, presents novel questions regarding mRNA localization and translation.
- Further research is needed to elucidate the precise roles of the SL and its associated motifs in dinoflagellate gene expression and cellular processes.
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