Male-Biased Aganglionic Megacolon in the TashT Mouse Line Due to Perturbation of Silencer Elements in a Large Gene Desert of Chromosome 10

Bergeron, Karl-F.; Cardinal, Tatiana; Touré, Aboubacrine M.; Béland, Mélanie; Raiwet, Diana L.; Silversides, David W. et Pilon, Nicolas (2015). « Male-Biased Aganglionic Megacolon in the TashT Mouse Line Due to Perturbation of Silencer Elements in a Large Gene Desert of Chromosome 10 ». PLOS Genetics, 11(3), e1005093.

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Résumé

Neural crest cells (NCC) are a transient migratory cell population that generates diverse cell types such as neurons and glia of the enteric nervous system (ENS). Via an insertional mutation screen for loci affecting NCC development in mice, we identified one line—named TashT—that displays a partially penetrant aganglionic megacolon phenotype in a strong male-biased manner. Interestingly, this phenotype is highly reminiscent of human Hirschsprung’s disease, a neurocristopathy with a still unexplained male sex bias. In contrast to the megacolon phenotype, colonic aganglionosis is almost fully penetrant in homozygous TashT animals. The sex bias in megacolon expressivity can be explained by the fact that the male ENS ends, on average, around a “tipping point” of minimal colonic ganglionosis while the female ENS ends, on average, just beyond it. Detailed analysis of embryonic intestines revealed that aganglionosis in homozygous TashT animals is due to slower migration of enteric NCC. The TashT insertional mutation is localized in a gene desert containing multiple highly conserved elements that exhibit repressive activity in reporter assays. RNAseq analyses and 3C assays revealed that the TashT insertion results, at least in part, in NCC-specific relief of repression of the uncharacterized gene Fam162b; an outcome independently confirmed via transient transgenesis. The transcriptional signature of enteric NCC from homozygous TashT embryos is also characterized by the deregulation of genes encoding members of the most important signaling pathways for ENS formation—Gdnf/Ret and Edn3/Ednrb—and, intriguingly, the downregulation of specific subsets of X-linked genes. In conclusion, this study not only allowed the identification of Fam162b coding and regulatory sequences as novel candidate loci for Hirschsprung’s disease but also provides important new insights into its male sex bias.

Type:	Article de revue scientifique
Mots-clés ou Sujets:	Aganglionic Megacolon, Hirschsprung’s disease, TashT, Chromosome 10
Unité d'appartenance:	Centres institutionnels > Centre de recherches biomédicales (BIOMED) Faculté des sciences > Département des sciences biologiques
Déposé par:	Jean-Jacques Rondeau
Date de dépôt:	07 déc. 2018 09:13
Dernière modification:	07 déc. 2018 09:13
Adresse URL :	http://archipel.uqam.ca/id/eprint/11970

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