Bmp suppression in mangrove killifish embryos causes a split in the body axis

Area of Science:

• Developmental Biology
• Genetics
• Evolutionary Biology

Background:

• Bone morphogenetic proteins (Bmp) are crucial for establishing the vertebrate body plan, particularly the dorsal-ventral axis.
• While Bmp signaling is conserved across vertebrates, its developmental outcomes can vary significantly between species.

Purpose of the Study:

• To investigate the role of Bmp signaling in embryonic development of the mangrove killifish, Kryptolebias marmoratus.
• To characterize the effects of Bmp pathway inhibition on axis formation and embryonic morphogenesis in this species.

Main Methods:

• Embryos of Kryptolebias marmoratus were exposed to the Bmp inhibitor dorsomorphin (DM) at specific stages and doses.
• Phenotypic analysis was performed to observe the impact of DM exposure on epiboly, yolk syncytial layer (YSL) movements, and anterior-posterior (AP) axis formation.

Main Results:

• Bmp signaling is essential for epiboly, YSL movements, and AP axis formation in Kryptolebias marmoratus embryos.
• Exposure to DM resulted in three distinct morphologies, including a novel "splitbody" phenotype.
• The splitbody phenotype featured a severely shortened AP axis with bilaterally split neural tube, somites, and notochord, and detached posterior neural tissues.

Conclusions:

• Bmp signaling plays a critical role in multiple aspects of embryonic development in the mangrove killifish.
• The unique splitbody phenotype highlights species-specific variations in the consequences of modifying conserved developmental pathways like Bmp signaling.
• This study underscores the importance of considering species-specific responses when studying developmental mechanisms across vertebrates.