Furry regulates organizer formation and gastrulation movements in Xenopus

CERVINO, AILEN; CIRIO, MARIA CECILIA; HUKRIEDE, NEIL A.

Congreso; IX Latin American Society for Developmental Biology Meeting; 2017

Latin American Society for Developmental Biology

In vertebrates, the establishment of the body plan is coordinated by a dynamic group of cells with morphogenic and inductive properties named the Spemann-Mangold organizer in Xenopus. Lhx1, is initially expressed in the organizer and encodes a LIM homeobox transcription factor whose function is required for establishing the embryonic axis. We previously found the protein Furry (Fry) associated to the Lhx1 transcriptional complex, and shown they act together to drive specification of the kidney field in Xenopus. Fry is expressed in the axial mesoderm and later in the notochord and acts as a transcriptional co-repressor of microRNAs in Xenopus embryos. Unlike Lhx1, little is known about the function of Fry in early development and its role in gastrulation and axis formation. We investigated the expression pattern of fry by in situ hybridization and found that its mRNA is present in the dorsal and ventral involuting marginal zone of the gastrula. Dorsal depletion of fry with a validated morpholino results in a reduced expression domain of the organizer genes goosecoid and chordin, and absence of dorsal expression of the pan-mesoderm marker brachyury indicating Fry is required for organizer formation. Fry-depleted embryos also exhibit blastopore closure defects and axial mesoderm convergent extension impairment gauged by the expression domain of the notochord homeobox gene, not. Interestingly, when fry was ventrally-depleted expression of organizer markers is unaffected whereas the gastrulation movements are compromised in these embryos. Together, our results suggest that Fry has a dual role in early development: it is required in dorsal tissues for mesoderm specification and in both ventral and dorsal tissues for gastrulation movements.