Control of growth and gut maturation by genes and the associated lncRNA .

During embryonic development, genes participate in the building of a functional digestive system in metazoans, and genetic conditions involving these genes lead to important, sometimes lethal, growth retardation. Recently, this phenotype was obtained after deletion of , the antisense growth-associated long noncoding RNA (lncRNA) located between and In this study, we have analyzed the function of genes in delayed growth trajectories by looking at several nested targeted deficiencies of the mouse cluster. Mutant pups were severely stunted during the suckling period, but many recovered after weaning. After comparing seven distinct alleles, including CRISPR/Cas9 deletions involving , we identified as the critical component for the gut to maintain milk-digestive competence. This essential function could be abrogated by the dominant-negative effect of as shown by a genetic rescue approach, thus further illustrating the importance of posterior prevalence in gene function. A role for the lncRNA in the control of postnatal growth could not be corroborated.