Biology subjects

Catela, C.

Publications and source records attributed to Catela, C..

4 recordsLinked to original sources

bioRxiv2024

The Iroquois (Iro/Irx) homeobox genes are conserved Hox targets involved in motor neuron development

The Iroquois (Iro/Irx) homeobox genes encode transcription factors with fundamental roles in animal development. Despite their link to various congenital conditions in humans, our understanding of Iro/Irx gene expression, function, and regulation remains incomplete. Here, we conducted a systematic expression analysis of all six mouse Irx genes in the embryonic spinal cord. We found five Irx genes (Irx1, Irx2, Irx3, Irx5, and Irx6) to be confined mostly to ventral spinal domains, offering new molecular markers for specific groups of post-mitotic motor neurons (MNs). Further, we engineered Irx2, Irx5, and Irx6 mouse mutants and uncovered essential but distinct roles for Irx2 and Irx6 in MN development. Last, we found that the highly conserved regulators of MN development across species, the HOX proteins, directly control Irx gene expression both in mouse and C. elegans MNs, critically expanding the repertoire of HOX target genes in the developing nervous system. Altogether, our study provides important insights into Iro/Irx expression and function in the developing spinal cord, and uncovers an ancient gene regulatory relationship between HOX and Iro/Irx genes.

developmental biology↗

bioRxiv2021

Control of spinal motor neuron terminal differentiation through sustained Hoxc8 gene activity

Spinal motor neurons (MNs) constitute cellular substrates for several movement disorders. Although their early development has received much attention, how spinal MNs become and remain terminally differentiated is poorly understood. Here, we determined the transcriptome of mouse brachial MNs at embryonic and postnatal stages. We found that genes encoding homeodomain (HOX, LIM) transcription factors (TFs), previously implicated in early MN development, continue to be expressed postnatally, suggesting later functions. To test this, we inactivated Hoxc8 at successive stages of MN development. We found that Hoxc8 is not only required to establish but also maintain expression of several MN terminal differentiation markers. Furthermore, we uncovered novel TFs with continuous MN expression, a Hoxc8 dependency for maintained expression of Iroquois (Irx) homeodomain TFs, and a new role for Irx2 in MN development. Our findings dovetail recent observations in C. elegans MNs, pointing toward an evolutionarily conserved role for Hox in neuronal terminal differentiation.

developmental biology↗

bioRxiv2020

FGF signaling regulates development through combinatorial transduction pathways and by modulating cellular adhesion

FGFs are key developmental regulators which engage a signal transduction cascade through receptor tyrosine kinases, typically involving ERK1/2, PI3K/AKT, and other effectors. However, it remains unknown if all FGF activities depend on kinase activity or these canonical signal transduction cascades. To address these questions, we generated allelic series of knock-in Fgfr1 and Fgfr2 mouse strains, carrying point mutations that disrupt binding of signaling effectors to the receptors, alone or in combination. We also produced a kinase dead allele of Fgfr2 which broadly phenocopies the null mutant. When interrogated in cranial neural crest cells, point mutations in either receptor revealed discrete functions for signaling pathways in specific craniofacial contexts, but failed to recapitulate the single or double null mutant phenotypes even in their most extensive combination. Furthermore, we found that together these signaling mutations abrogated the established FGF-induced signal transduction pathways, yet certain FGF functions such as cell-matrix and cell-cell adhesion remained unaffected. Our studies establish combinatorial roles of both Fgfr1 and Fgfr2 in development and identify novel kinase-dependent cell adhesion properties of FGF receptors, independent of well-established roles in intracellular signaling.Competing Interest StatementThe authors have declared no competing interest.View Full Text

developmental biology↗

bioRxiv2018

An ancient role for Collier/Olf/Ebf (COE)-type transcription factors in axial motor neuron development

BackgroundMammalian motor circuits display remarkable cellular diversity with hundreds of motor neuron (MN) subtypes innervating hundreds of different muscles. Extensive research on limb muscle-innervating MNs has begun to elucidate the genetic programs that control animal locomotion. In striking contrast, the molecular mechanisms underlying the development of axial muscle-innervating MNs, which control breathing and spinal alignment, are poorly studied.\n\nMethodsOur previous studies indicated that the function of the Collier/Olf/Ebf (COE) family of transcription factors (TFs) in axial MN development may be conserved from nematodes to simple chordates. Here, we examine the expression pattern of all four mouse COE family members (mEbf1-mEbf4) in spinal MNs and employ genetic approaches in both nematodes and mice to investigate their function in axial MN development.\n\nResultsWe report that mEbf1 and mEbf2 are expressed in distinct MN clusters (termed \"columns\") that innervate different axial muscles. Mouse Ebf1 is expressed in MNs of the hypaxial motor column (HMC), which is necessary for breathing, while mEbf2 is expressed in MNs of the medial motor column (MMC) that control spinal alignment. Our characterization of Ebf2 knock-out mice revealed a requirement for Ebf2 in the differentiation of a subset of MMC MNs, indicating molecular diversity within MMC neurons. Intriguingly, transgenic expression of mEbf1 or mEbf2 can rescue axial MN differentiation and locomotory defects in nematodes (Caenorhabditis elegans) lacking unc-3, the sole C. elegans ortholog of the COE family, suggesting functional conservation among mEbf1, mEbf2 and nematode UNC-3.\n\nConclusionsThese findings support the hypothesis that the genetic programs controlling axial MN development are deeply conserved across species, and further advance our understanding of such programs by revealing an essential role for Ebf2 in mouse axial MNs. Because human mutations in COE ortholgs lead to neurodevelopmental disorders characterized by motor developmental delay, our findings may advance our understanding of these human conditions.

developmental biology↗