Biology subjects

Ernest, J.

Publications and source records attributed to Ernest, J..

2 recordsLinked to original sources

bioRxiv2023

Allelic promoter variation causes a switch in reproductive tissue expression in an Arabidopsis exonuclease gene

Among candidate genes underlying the control components of apomixis, APOLLO is known for its strong linkage to apomeiosis in the genus Boechera. The gene has "apo-alleles", which are characterized by a set of linked apomixis-specific polymorphisms, and "sex-alleles". All apomictic{square}Boechera genotypes are heterozygous for the apo/sex-alleles, while all sexual genotypes are homozygous for sex-alleles. In this study, native and synthetic APOLLO promoters were characterized by detecting the expression level of the {beta}-glucuronidase (GUS) gene in Arabidopsis. Comparing various flower developmental stages in transgenic lines containing different constructs with 2 kb native transgenic lines revealed that changes to the APOLLO promoter causes shifts in tissue- and developmental-stage specificity of GUS expression. Importantly, several apomixis-specific polymorphisms in the 5UTR change the timing and location of GUS activity from somatic to reproductive tissues. These synthetic data simulate a plausible evolutionary process whereby apomixis-specific gene activity can be achieved.

plant biology↗

bioRxiv2021

GATA4 regionalizes intestinal metabolism and barrier function to prevent immunopathology

Different regions of the gastrointestinal tract have distinct digestive and absorptive functions, which may be locally disrupted by infection or autoimmune disease. Yet, the mechanisms underlying intestinal regionalization and its dysregulation in disease are not well understood. Here, we used mouse models, transcriptomics, and immune profiling to show that regional epithelial expression of the transcription factor GATA4 prevented adherent bacterial colonization and inflammation in the proximal small intestine by regulating retinol metabolism and luminal IgA. Loss of epithelial GATA4 expression increased mortality in mice infected with Citrobacter rodentium. In active celiac patients with villous atrophy, low GATA4 expression was associated with metabolic alterations, mucosal Actinobacillus, and increased IL-17 immunity. This study reveals broad impacts of GATA4-regulated intestinal regionalization and highlights an elaborate interdependence of intestinal metabolism, immunity, and microbiota in homeostasis and disease. One-sentence summaryEpithelial GATA4 regulates intestinal regionalization of bacterial colonization, metabolic pathways, and tissue immunity.

immunology↗