Project description:Aging is a time-dependent biological phenomenon governed by complex networks of regulatory components and their transitions over lifetime. Yet, there have been limited efforts to pin down age-associated networks and map their dynamic characteristics onto aging phenotypes. Here, we built time-course genetic regulatory networks of NAM/ATAF/CUC (NAC) transcription factors during the course of leaf aging in Arabidopsis, using causal regulatory relationships among NACs identified from mutants of 49 aging-associated NACs. These temporal networks revealed a regulatory inversion from activating to repressive regulatory modes at a pre-senescent stage. The inversion was governed by three hub NACs, and their mutants conferred earlier aging with altered expression of reactive oxygen species and salicylic acid response genes. Overexpression of the hub NACs delayed the regulatory inversion, rendering delayed age-dependent cell death. We conclude that the regulatory inversion in NAC networks at a pre-senescent stage directs when age-dependent cell death should proceed in plants.
Project description:Aging is a time-dependent biological phenomenon governed by complex networks of regulatory components and their transitions over lifetime. Yet, there have been limited efforts to pin down age-associated networks and map their dynamic characteristics onto aging phenotypes. Here, we built time-course genetic regulatory networks of NAM/ATAF/CUC (NAC) transcription factors during the course of leaf aging in Arabidopsis, using causal regulatory relationships among NACs identified from mutants of 49 aging-associated NACs. These temporal networks revealed a regulatory inversion from activating to repressive regulatory modes at a pre-senescent stage. The inversion was governed by three hub NACs, and their mutants conferred earlier aging with altered expression of reactive oxygen species and salicylic acid response genes. Overexpression of the hub NACs delayed the regulatory inversion, rendering delayed age-dependent cell death. We conclude that the regulatory inversion in NAC networks at a pre-senescent stage directs when age-dependent cell death should proceed in plants.
Project description:To understand how the NAC transcription factor KIL1 regulates age-induced senescence and cell death in maize silks, we need to get a genome-wide view on its downstream targets. We propose to compare the transcriptome profiles of GOF and LOF transgenic silk tissue with the profile of wild-type B104 silk. 1 cm of basal part of silk from rings 6-10 from plants harboring the dominant-negative repressor proSILK1:KIL1-SRDX, proSILK1:KIL1 overexpressing line, and wild type B104 will be harvested at 11 DASE. This will allow to compare and contrast the expression profiles of KIL1 LOF and GOF mutants with transcriptome data derived from wild type senescent silk.
Project description:Expression of Shh in the limb is dependent on a distant enhancer located 850kb away from the gene promoter. We performed chromatin conformation capture (4C-Seq) analysis of the Shh locus in E11.5 mouse limbs so as to better understand the relationship between this regulatory interaction and the structural organisation of the locus. The experiments were performed on wild-type animals as well as on animals carrying an engineered chromosomal inversion (INV(6-C2) (INV6)) . The different viewpoints used (Shh, ZRS, Nom1, Rbm33, Rnf32) enable to characterize the 3D organisation of the locus in the different contexts. The inversion INV6 disrupts the normal topological organisation of the Shh locus in a compact 3D-domain and prevents the physical and regulatory interaction between Shh and its limb enhancer, even though the genomic distance separating the two elements is reduced compared to WT.
Project description:We evaluated if a higher plane of maternal nutrition during late gestation and weaning age alters the offspring’s Longissimus muscle (LM) transcriptome. A microarray analysis was performed in LM samples of early (EW) and normal weaned (NW) Angus × Simmental calves born from cows that were grazing endophyte-infected tall fescue/red clover pastures with no supplement (low plane of nutrition (LPN)), or supplemented with 2.3 kg of dried distiller’s grains with solubles and soyhulls (70% DDGS/30% soyhulls) (medium plane of nutrition (MPN)) during the last 90 days of gestation. Biopsies were harvested at 78, 187 and 354 days of age. Bioinformatics analysis highlighted that offspring transcriptome did not respond markedly to cow plane of nutrition, resulting in only 13 differentially expressed genes. However, weaning age and a high-starch diet strongly impacted the transcriptome, especially the immediate activation of the lipogenic program in EW steers. In addition, between 78 and 187 days of age, these animals had an activation of the innate immune system due presumably to macrophage infiltration in intramuscular fat. Between 187 and 354 days of age (i.e. the fattening phase), NW steers had an activation of the lipogenic transcriptome machinery, while EW steers had a clear gene transcription inhibition. The latter appears to have occurred through the epigenetic control of histone acetylases, which were down-regulated. Higher cow plane of nutrition alone affected 35 genes in the LM of steers that underscore the presence of a mechanism of macrophage infiltration likely originating from localized oxidative stress as a result of increased levels of hypoplasia and hypertrophy in LM.
Project description:We systematically investigated the lncRNA and mRNA temporal expression profile of the female chicken brain by high-throughput sequencing 8 stages across their entire lifespan. We identified and classified 39,907 putative lncRNAs, and predicted the potential biological functions of lncRNAs based on WGCNA. Temporal expression patterns were investigated based on a set of age-dependent genes, results showed that genes functioned in development, synapse and axon exhibited a progressive decay; genes related to immune response were up-regulated with age, And some genes showed inversion of their temporal profiles. These results demonstrated dynamic changes in lncRNA and mRNA with age, which may reflect changes in regulation of transcriptional networks and provides non-coding RNA gene candidates for further studies. It would be vital significance in avian epidemic prevention and contribute to comprehensively understand the molecular mechanisms of chicken breeding and reproduction. Besides, birds, as important species to bridge the evolutionary gap between mammals and other vertebrates, would contribute to further improve the understanding of the role in evolution.