Molecular mechanisms of embryonic tail development in the self-fertilizing mangrove killifish Kryptolebias marmoratus.

Hussein A. Saud,Ronny Van Aerle,Jaebum Kim,Paul A. O'Neill,Yosuke Ono,Bas Verbruggen,Tetsuhiro Kudoh,Jae-Seong Lee,Brian C. Ring

doi:10.1242/dev.199675

Abstract

ABSTRACTUsing the self-fertilizing mangrove killifish, we characterized two mutants, shorttail (stl) and balltail (btl). These mutants showed abnormalities in the posterior notochord and muscle development. Taking advantage of a highly inbred isogenic strain of the species, we rapidly identified the mutated genes, noto and msgn1 in the stl and btl mutants, respectively, using a single lane of RNA sequencing without the need of a reference genome or genetic mapping techniques. Next, we confirmed a conserved morphant phenotype in medaka and demonstrate a crucial role of noto and msgn1 in cell sorting between the axial and paraxial part of the tail mesoderm. This novel system could substantially accelerate future small-scale forward-genetic screening and identification of mutations. Therefore, the mangrove killifish could be used as a complementary system alongside existing models for future molecular genetic studies.

Highlights

IntroductionThe embryo is organized as a head, trunk and tail along the anterior to posterior axis
Within vertebrate species, the embryo is organized as a head, trunk and tail along the anterior to posterior axis
The role of noto homologues has been investigated in several model animals, including mice, Xenopus and zebrafish, demonstrating that noto plays a crucial role in notochord development (Talbot et al, 1995; Halpern et al, 1995; Odenthal et al, 1996; Melby et al, 1996; Abdelkhalek et al, 2004; Yamanaka et al, 2007; Goto et al, 2017)

Summary

Introduction

The embryo is organized as a head, trunk and tail along the anterior to posterior axis. In zebrafish, the trunk cell fates are specified at gastrula stage around the blastoderm margin where the dorsal-most area gives rise to the notochord, and the lateral side to trunk somites and spinal cord (Kimmel et al, 1990; Woo et al, 1995; Kudoh et al, 2004). At this stage, the cells for tail somites and spinal cord are maintained along the ventral side of the embryo (Kudoh et al, 2004). The fundamental role of the tail bud may be conserved in all vertebrate animals, due to their differences in embryonic morphology and size, gene expression patterns and the mechanisms by which the tail bud regulates tail tissue specification and patterning vary depending on the species (Finch et al, 2010; Mourabit et al, 2014)

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