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Summary MicroRNAs (miRNAs) are essential regulators of gene expression in metazoans and plants. In plants, most miRNAs are generated from primary miRNA transcripts (pri‐miRNAs), which are processed by the Dicer‐like 1 (DCL1) complex along with accessory proteins.Serrate‐Associated Protein 1 (SEAP1), a conserved splicing‐related protein, has been studied in human and yeast. However, the functions of SEAP1 in plants remain elusive.Lack ofSEAP1results in embryo lethality and knockdown ofSEAP1by an artificial miRNA (amiRSEAP1) causes pleiotropic developmental defects and reduction in miRNA accumulation. SEAP1 associates with the DCL1 complex, and may promote the interaction of the DCL1 complexes with pri‐miRNAs. SEAP1 also enhances pri‐miRNA accumulation, but does not affect pri‐miRNA transcription, suggesting it may indirectly or directly stabilize pri‐miRNAs. In addition, SEAP1 affects the splicing of some pri‐miRNAs and intron retention of messenger RNAs at global levels.Our findings uncover both conserved and novel functions of SEAP1 in plants. Besides the role as a splicing factor, SEPA1 may promote miRNA biogenesis by positively modulating pri‐miRNA splicing, processing and/or stability.
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Expression of endogenous Anopheles gambiae microRNAs using an Anopheles gambiae densovirus (AgDNV) intronic expression system
Abstract BackgroundAnopheles gambiaedensovirus (AgDNV) is a highly species-specific parvovirus that reaches high titers in adultAnopheles gambiaemosquitoes with few transcriptomic effects and minimal significant fitness effects. Given these characteristics, AgDNV has been proposed as a viral vector for basic research and mosquito control. Previous work created an AgDNV co-expression system with a wild-type AgDNV helper plasmid and a transducing plasmid expressing enhanced green fluorescent protein (EGFP) that can be used to co-transfect cells to generate infectious recombinant transducing AgDNV virions. Generated virions infect theAn. gambiaemidgut, fat body, and ovaries, yet this viral vector system is limited in the size of transgenes that can be expressed due to capsid packaging limitations. MethodsConsidering these size constraints, we created an artificial intron within the EGFP gene of the transducing construct that can express small pieces of genetic material such as microRNAs (miRNAs), microRNA sponges, or other small sequences. Placement of this intron in EGFP created a fluorescent reporter such that incorrect splicing produces a frameshift mutation in EGFP and an early stop codon, whereas correct splicing results in normal EGFP expression and co-transcription of the intronic genetic cargo. A selection of miRNAs with predicted or demonstrated importance in mosquito immunity and reproduction with expression localized to the fat body or ovaries were chosen as intronic cargo. Construct expression and splicing was evaluated, and the impact of miRNA expression on putative miRNA targets was measuredin vitroandin vivo. ResultsThe created intron was correctly spliced in cells and mosquitoes; however, miRNA delivery resulted in inconsistent changes to miRNA and predicted target gene transcript levels—possibly due to organ-specific miRNA expression or inaccurate putative target predictions leading to miRNA–target gene sequence mismatch. ConclusionsAlthough our results on target gene expression were inconsistent, with optimization this viral vector and developed intron have potential as an expression tool withinAn. gambiaemosquitoes or cell lines. Graphical Abstract
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- Award ID(s):
- 1645331
- PAR ID:
- 10629243
- Publisher / Repository:
- Springer Science + Business Media
- Date Published:
- Journal Name:
- Parasites & Vectors
- Volume:
- 18
- Issue:
- 1
- ISSN:
- 1756-3305
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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