Post-transcriptional regulation of wnt8a is essential to zebrafish axis development

• Published in: Developmental biology 2014-02, Vol.386 (1), p.53-63
• Main Authors: Wylie, Annika D., Fleming, Jo-Ann G.W., Whitener, Amy E., Lekven, Arne C.
• Format: Article
• Language: English
• Subjects: Animals; Axis patterning; Base Sequence; Body Patterning; Cytoskeletal Proteins - genetics; Danio rerio; Freshwater; Gene Expression Regulation, Developmental; Green Fluorescent Proteins - metabolism; MicroRNAs - metabolism; miR-430; Molecular Sequence Data; Neural posteriorization; Neurons - metabolism; Phenotype; Post-transcriptional; RNA Processing, Post-Transcriptional; RNA, Messenger - metabolism; Signal Transduction; Transgenes; UTR; Wnt Proteins - genetics; wnt8a; Zebrafish; Zebrafish - embryology; Zebrafish - genetics; Zebrafish Proteins - genetics
• ISSN: 0012-1606; 1095-564X
• DOI: 10.1016/j.ydbio.2013.12.003

wnt8a Is essential for normal patterning during vertebrate embryonic development, and either gain or loss-of-function gene dysregulation results in severe axis malformations. The zebrafish wnt8a locus is structured such that transcripts may possess two regulatory 3' untranslated regions (UTRs), raising the possibility of post-transcriptional regulation as an important mode of wnt8a signaling control. To determine whether both UTRs contribute to post-transcriptional wnt8a gene regulation, each UTR (UTR1 and UTR2) was tested in transient and transgenic reporter assays. Both UTRs suppress EGFP reporter expression in cis, with UTR2 exhibiting a more pronounced effect. UTR2 contains a 6 base sequence necessary for UTR2 regulatory function that is complementary to the seed of the microRNA, miR-430. A target protector morpholino that overlaps the seed complement stabilizes both reporter mRNAs and wnt8a mRNAs, and produces phenotypic abnormalities consistent with wnt8a gain-of-function. In rescue assays, specific functions can be attributed to each of the two wnt8a proteins encoded by the locus. An interplay of wnt8a.1 and wnt8a.2 regulates neural and mesodermal patterning and morphogenesis as well as patterning between brain subdivisions. Thus, post-transcriptional control of wnt8a is essential to fine tune the balance of the signaling outputs of the complex wnt8a locus. •Zebrafish wnt8a transcripts may possess two regulatory UTR elements.•Both UTR elements suppress gene expression in cis.•UTR2 contains a complement to the miR-430 seed, which is essential for regulation.•Protection of UTR2 produces a wnt8a gain-of-function phenotype•Rescue assays reveal independent functions for wnt8a.1 and wnt8a.2.