Biology subjects

Feregrino, C.

Publications and source records attributed to Feregrino, C..

7 recordsLinked to original sources

bioRxiv2026

Evolution and mechanism of MEIS2-mediated forelimb specialization in bats

The genomic basis of limb adaptations in tetrapods is thought to be largely driven by changes in gene regulation. However, the mechanisms by which regulatory programs evolve are not well understood. In bats, wing membrane development has been shown to be associated with expression of the transcription factor MEIS2 in the interdigital tissue of the forelimb. However, MEIS2 alone is insufficient to recapitulate wing morphology, suggesting that its regulatory context has also undergone divergence. Here, we integrate functional genomics with sequence-to-function deep learning to dissect both the mechanistic and evolutionary roles of MEIS2 in bat forelimb development. Using models trained on embryonic limb data from bat and mouse, we identify a strong association between MEIS2 binding and the transcription factor TWIST1, a finding which is supported by single-cell transcriptomic analyses. To investigate the evolutionary dimension, we applied these models across more than 100 genomes, including extant bats, closely related species, and reconstructed ancestors. This analysis identified divergences in regulatory regions, which likely contribute to bat-specific forelimb expression of genes that lead to wing morphogenesis. Notably, these changes are prominent in the regulatory domains of the MEIS dimerization partner PBX1, indicating coordinated regulatory evolution. Together, our results demonstrate that the evolution of a complex morphological trait involves coordinated changes in both trans-regulatory environments and cis-regulatory landscapes. More broadly, this study provides a framework for integrating deep learning with comparative and functional genomics to investigate regulatory evolution.

evolutionary biology↗

bioRxiv2024

Comparative single-cell analyses reveal evolutionary repurposing of a conserved gene program in bat wing development

Bats are the only mammals capable of self-powered flight, an evolutionary innovation based on the transformation of forelimbs into wings. The bat wing is characterized by an extreme elongation of the second to fifth digits and a wing membrane called chiropatagium connecting them. Here we investigated the developmental and cellular origin of this structure by comparing bat and mouse limbs using omics tools and single-cell analyses. Despite the substantial morphological differences between the species, we observed an overall conservation of cell populations and gene expression patterns including interdigital apoptosis. Single-cell analyses of micro-dissected embryonic chiropatagium identified a specific fibroblast population, independent of apoptosis-associated interdigital cells, as the origin of this tissue. These distal cells express a conserved gene program including the transcription factors MEIS2 and TBX3, which are commonly known to specify and pattern the early proximal limb. Transgenic ectopic expression of MEIS2 and TBX3 in mouse distal limb cells resulted in the activation of genes expressed during wing development and phenotypic changes related to wing morphology, such as the fusion of digits. Our results elucidate fundamental molecular mechanisms of bat wing development and illustrate how drastic morphological changes can be achieved through repurposing of existing developmental programs during evolution.

evolutionary biology↗

bioRxiv2024

Distinct Gene Regulatory Dynamics Drive Skeletogenic Cell Fate Convergence During Vertebrate Embryogenesis

Cell type repertoires have expanded extensively in metazoan animals, with some clade-specific cells being paramount to their evolutionary success. A prime example are the skeletogenic cells of vertebrates that form the basis of their developing endoskeletons. Depending on anatomical location, these cells originate from three different embryonic precursor lineages - the neural crest, the somites, and the lateral plate mesoderm - yet they converge developmentally towards similar cellular phenotypes. Furthermore, these lineages have gained skeletogenic competency at distinct timepoints during vertebrate evolution, thus questioning to what extent different parts of the vertebrate skeleton rely on truly homologous cell types. Here, we investigate how lineage-specific molecular properties of the three precursor pools are integrated at the gene regulatory level, to allow for phenotypic convergence towards a skeletogenic cell fate. Using single-cell transcriptomics and chromatin accessibility profiling along the precursor-to-skeletogenic cell continuum, we examine the gene regulatory dynamics associated with this cell fate convergence. We find that distinct transcription factor profiles are inherited from the three precursor states, and that lineage-specific enhancer elements integrate these different inputs at the cis-regulatory level, to execute a core skeletogenic program. We propose a lineage-specific gene regulatory logic for skeletogenic convergence from three embryonic precursor pools. Early skeletal cells in different body parts thus share only a partial deep homology. This regulatory uncoupling may render them amenable to individualized selection, to help to define distinct morphologies and biomaterial properties in the different parts of the vertebrate skeleton.

developmental biology↗

bioRxiv2023

Self-organized BMP signaling dynamics underlie the development and evolution of tetrapod digit patterns

Repeating patterns of synovial joints are a highly conserved feature of articulated digits, with variations in joint number and location giving rise to a diverse range of digit morphologies and limb functions across the tetrapod clade. During development, joints form iteratively within the growing digit ray, as a population of distal progenitors alternately specifies joint and phalanx cell fates to segment the digit into distinct elements. Whilst numerous molecular pathways have been implicated in this fate choice, it remains unclear how they give rise to a repeating pattern. Here, using single cell RNA-sequencing and spatial gene expression profiling, we investigate the transcriptional dynamics of interphalangeal joint specification in vivo. Combined with mathematical modelling, we predict that interactions within the BMP signaling pathway - between the ligand GDF5, the inhibitor NOG, and the intracellular effector pSMAD - result in a self-organizing Turing system that forms periodic joint patterns. Our model is able to recapitulate the spatiotemporal gene expression dynamics observed in vivo, as well as phenocopy digit malformations caused by BMP pathway perturbations. By contrasting in silico simulations with in vivo morphometrics of two morphologically distinct digits, we show how changes in signaling parameters and growth dynamics can result in variations in the size and number of phalanges. Together, our results reveal a self-organizing mechanism that underpins tetrapod digit patterning and its evolvability, and, more broadly, illustrate how Turing systems based on a single molecular pathway may generate complex repetitive patterns in a wide variety of organisms.

developmental biology↗

bioRxiv2021

Extracellular matrix gene expression signatures as cell type and cell state identifiers

Transcriptomic signatures based on cellular mRNA expression profiles can be used to categorize cell types and states. Yet whether different functional groups of genes perform better or worse in this process remains largely unexplored. Here we test the core matrisome - that is, all genes coding for structural proteins of the extracellular matrix - for its ability to delineate distinct cell types in embryonic single-cell RNA-sequencing (scRNA-seq) data. We show that even though expressed core matrisome genes correspond to less than 2% of an entire cellular transcriptome, their RNA expression levels suffice to recapitulate important aspects of cell type-specific clustering. Notably, using scRNA-seq data from the embryonic limb, we demonstrate that core matrisome gene expression outperforms random gene subsets of similar sizes and can match and exceed the predictive power of transcription factors. While transcription factor signatures generally perform better in predicting cell types at early stages of chicken and mouse limb development, i.e., when cells are less differentiated, the information content of the core matrisome signature increases in more differentiated cells. Our findings suggest that each cell type produces its own unique extracellular matrix, or matreotype, which becomes progressively more refined and cell type-specific as embryonic tissues mature. HighlightsO_LICell types produce unique extracellular matrix compositions C_LIO_LIDynamic extracellular matrix gene expression profiles hold predictive power for cell type and cell state identification C_LI

systems biology↗

bioRxiv2021

Assessing evolutionary and developmental transcriptome dynamics in homologous cell types

BackgroundDuring development, complex organ patterns emerge through the precise temporal and spatial specification of different cell types. On an evolutionary timescale, these patterns can change, resulting in morphological diversification. It is generally believed that homologous anatomical structures are built - largely - by homologous cell types. However, whether a common evolutionary origin of such cell types is always reflected in the conservation of their intrinsic transcriptional specification programs is less clear. ResultsHere, using a paradigm of morphological diversification, the tetrapod limb, and singlecell RNA-sequencing data from two distantly related species, chicken and mouse, we assessed the transcriptional dynamics of homologous cell types during embryonic patterning. We developed a user-friendly bioinformatics workflow to detect gene co-expression modules and test for their conservation across developmental stages and species boundaries. Using mouse limb data as reference, we identified 19 gene co-expression modules with varying tissue or cell type-restricted activities. Testing for co-expression conservation revealed modules with high evolutionary turnover, while others seemed maintained - to different degrees, in module make-up, density or connectivity - over developmental and evolutionary timescales. ConclusionsWe present an approach to identify evolutionary and developmental dynamics in gene co-expression modules during patterning-relevant stages of homologous cell type specification.

developmental biology↗

bioRxiv2019

A Single-cell Transcriptomic Atlas of the Developing Chicken Limb

BackgroundThrough precise implementation of distinct cell type specification programs, differentially regulated in both space and time, complex patterns emerge during organogenesis. Thanks to its easy experimental accessibility, the developing chicken limb has long served as a paradigm to study vertebrate pattern formation. Through decades worth of research, we now have a firm grasp on the molecular mechanisms driving limb formation at the tissue-level. However, to elucidate the dynamic interplay between transcriptional cell type specification programs and pattern formation at its relevant cellular scale, we lack appropriately resolved molecular data at the genome-wide level. Here, making use of droplet-based single-cell RNA-sequencing, we catalogue the developmental emergence of distinct tissue types and their transcriptome dynamics in the distal chicken limb, the so-called autopod, at cellular resolution.\n\nResultsUsing single-cell RNA-sequencing technology, we sequenced a total of 17,628 cells coming from three key developmental stages of chicken autopod patterning. Overall, we identified 23 cell populations with distinct transcriptional profiles. Amongst them were small, albeit essential populations like the apical ectodermal ridge, demonstrating the ability to detect even rare cell types. Moreover, we uncovered the existence of molecularly distinct sub-populations within previously defined compartments of the developing limb, some of which have important signaling functions during autopod pattern formation. Finally, we inferred gene co-expression modules that coincide with distinct tissue types across developmental time, and used them to track patterning-relevant cell populations of the forming digits.\n\nConclusionsWe provide a comprehensive functional genomics resource to study the molecular effectors of chicken limb patterning at cellular resolution. Our single-cell transcriptomic atlas captures all major cell populations of the developing autopod, and highlights the transcriptional complexity in many of its components. Finally, integrating our data-set with other single-cell transcriptomics resources will enable researchers to assess molecular similarities in orthologous cell types across the major tetrapod clades, and provide an extensive candidate gene list to functionally test cell-type-specific drivers of limb morphological diversification.

developmental biology↗