Cdx ParaHox genes acquired distinct developmental roles after gene duplication in vertebrate evolution

BACKGROUND: The functional consequences of whole genome duplications in vertebrate evolution are not fully understood. It remains unclear, for instance, why paralogues were retained in some gene families but extensively lost in others. Cdx homeobox genes encode conserved transcription factors controlling posterior development across diverse bilaterians. These genes are part of the ParaHox gene cluster. Multiple Cdx copies were retained after genome duplication, raising questions about how functional divergence, overlap, and redundancy respectively contributed to their retention and evolutionary fate. RESULTS: We examined the degree of regulatory and functional overlap between the three vertebrate Cdx genes using single and triple morpholino knock-down in Xenopus tropicalis followed by RNA-seq. We found that one paralogue, Cdx4, has a much stronger effect on gene expression than the others, including a strong regulatory effect on FGF and Wnt genes. Functional annotation revealed distinct and overlapping roles and subtly different temporal windows of action for each gene. The data also reveal a colinear-like effect of Cdx genes on Hox genes, with repression of Hox paralogy groups 1 and 2, and activation increasing from Hox group 5 to 11. We also highlight cases in which duplicated genes regulate distinct paralogous targets revealing pathway elaboration after whole genome duplication. CONCLUSIONS: Despite shared core pathways, Cdx paralogues have acquired distinct regulatory roles during development. This implies that the degree of functional overlap between paralogues is relatively low and that gene expression pattern alone should be used with caution when investigating the functional evolution of duplicated genes. We therefore suggest that developmental programmes were extensively rewired after whole genome duplication in the early evolution of vertebrates

Cdx ParaHox genes acquired distinct developmental roles after gene duplication in vertebrate evolution

Background: The functional consequences of whole genome duplications in vertebrate evolution are not fully understood. It remains unclear, for instance, why paralogues were retained in some gene families but extensively lost in others. Cdx homeobox genes encode conserved transcription factors controlling posterior development across diverse bilaterians. These genes are part of the ParaHox gene cluster. Multiple Cdx copies were retained after genome duplication, raising questions about how functional divergence, overlap, and redundancy respectively contributed to their retention and evolutionary fate. / Results: We examined the degree of regulatory and functional overlap between the three vertebrate Cdx genes using single and triple morpholino knock-down in Xenopus tropicalis followed by RNA-seq. We found that one paralogue, Cdx4, has a much stronger effect on gene expression than the others, including a strong regulatory effect on FGF and Wnt genes. Functional annotation revealed distinct and overlapping roles and subtly different temporal windows of action for each gene. The data also reveal a colinear-like effect of Cdx genes on Hox genes, with repression of Hox paralogy groups 1 and 2, and activation increasing from Hox group 5 to 11. We also highlight cases in which duplicated genes regulate distinct paralogous targets revealing pathway elaboration after whole genome duplication. / Conclusions: Despite shared core pathways, Cdx paralogues have acquired distinct regulatory roles during development. This implies that the degree of functional overlap between paralogues is relatively low and that gene expression pattern alone should be used with caution when investigating the functional evolution of duplicated genes. We therefore suggest that developmental programmes were extensively rewired after whole genome duplication in the early evolution of vertebrates

The cat and the ball of yarn. Interweaving the threads of the history and restoration of the villa Savoye (1970- 1986)

[EN] The essay, the first of two writings, reconstructs the events of the generation of historians who between the seventies and mid-eighties studied and interpreted the written and designed works by Le Corbusier. This picture is part of the reading of different phases of the restoration of villa Savoye conducted by architect en chef Ivan Gury after the first operation by Jean Dubuisson, leading to a season of infinite authorial restorations of the modern. The authors deal with the complex issue of the interpretation of Le Corbusier’s works during the formation phase of the history of contemporary architecture, when the sources are almost all accessible and the literature on the subject explodes. The text investigates unpublished materials and documents, offering a new interpretation both of the villa Savoye and of the texts on the French-Swiss master.[FR] L’essai, le premier de deux écrits, reconstitue les événements de la génération d’historiens qui, entre les années 70 et le milieu des années 80, a étudié et interprété les œuvres de Le Corbusier, écrites et projetées. Cette image s’inscrit dans la lecture des différentes phases de restauration de la villa Savoye menée par l’architecte en chef Ivan Gury après un premier achèvement par Jean Dubuisson, ouvrant une saison de restaurations infinies du moderne d’auteur. Les auteurs abordent également la question complexe de l’interprétation des œuvres de Le Corbusier dans la phase de formation de l’histoire de l’architecture contemporaine, lorsque les sources sont presque toutes accessibles et que la littérature sur le sujet explose. Le texte explore des matériaux et des documents inédits, offrant une nouvelle interprétation à la fois de la villa Savoye et des textes sur le maître franco-suisse.[ES] El ensayo, el primero de dos escritos, reconstituye los acontecimientos de la generación de historiadores que, entre los años 70 y mediados de los 80, estudiaron e interpretaron las obras escritas y proyectadas por Le Corbusier. Esta imagen forma parte de la lectura de las diferentes fases de restauración de la Villa Savoye dirigidas por el arquitecto jefe Ivan Gury tras una primera realización de Jean Dubuisson, abriendo una época de interminables restauraciones de autor de lo moderno. Los autores también abordan la compleja cuestión de la interpretación de las obras de Le Corbusier en la fase de formación de la historia de la arquitectura contemporánea, cuando las fuentes están casi universalmente disponibles y la literatura sobre el tema se dispara. El texto explora materiales y documentos inéditos, ofreciendo una nueva interpretación tanto de la Villa Savoye como de los textos sobre el maestro franco-suizo.Caccia Gherardini, S.; Olmo, C. (2021). The cat and the ball of yarn. Interweaving the threads of the history and restoration of the villa Savoye (1970- 1986). LC. Revue de recherches sur Le Corbusier. 0(4):9-36. https://doi.org/10.4995/lc.2021.16215OJS9360

Cartographies of action research: searching for displacements of the epistemology of the South

The purpose of this paper is to discuss action research as one of the possibilities for the development of an epistemology of the South, in which scientific knowledge and other ecologies of knowledge can be linked. In this work, we propose a mapping of what has been developed on action research in Brazil, seeking to discuss this dimension of knowledge production from perspectives which seek to break the gap between colonizing and invisibilized science in the geopolitics of scientific knowledge. Thus, our proposal seeks to answer what has been produced on action research in Brazil, who are the actors that are developing this type of research and how it can be understood as belonging to an epistemology of the South

A dual-functional paramyxovirus F protein regulatory switch segment: activation and membrane fusion

Many viral fusion–mediating glycoproteins couple α-helical bundle formation to membrane merger, but have different methods for fusion activation. To study paramyxovirus-mediated fusion, we mutated the SV5 fusion (F) protein at conserved residues L447 and I449, which are adjacent to heptad repeat (HR) B and bind to a prominent cavity in the HRA trimeric coiled coil in the fusogenic six-helix bundle (6HB) structure. These analyses on residues L447 and I449, both in intact F protein and in 6HB, suggest a metamorphic region around these residues with dual structural roles. Mutation of L447 and I449 to aliphatic residues destabilizes the 6HB structure and attenuates fusion activity. Mutation of L447 and I449 to aromatic residues also destabilizes the 6HB structure despite promoting hyperactive fusion, indicating that 6HB stability alone does not dictate fusogenicity. Thus, residues L447 and I449 adjacent to HRB in paramyxovirus F have distinct roles in fusion activation and 6HB formation, suggesting this region is involved in a conformational switch

The Ascent, 1983 October 6

Student newspaper of Daemen College (formerly Rosary Hill College)

Crossed Concepts: Identity, Habitus and Reflexivity in a Revised Framework

Identity is in almost all discourses, perceptions and paradigms, from the social sciences to politics, the media and daily life, like a floating signifier for multiple meanings. In this sense it is less a concept than an umbrella term for different, even competing perspectives of individuals, collective bodies, ties and processes. Thus it represents, rather, a label or a gate for wider issues presupposing crossed concepts. Or concepts that we must cross in that conflation of reflexive lines, searching for a cohesive framework for our identities, plural and pluridimensional. Based on sociology, this text attempts to cross the notion of identity with two concepts – habitus and reflexivity – associated with the legacies of Pierre Bourdieu and Anthony Giddens, respectively, and similar circles. A way to articulate and update them with other authors and debates on contemporary culture, the individual and the biographical approach, which bring new insights into the personal and social production of difference(s)