Project description:Microbial communities respond to temperature with physiological adaptation and compositional turnover. Whether thermal selection of enzymes explains marine microbiome plasticity in response to temperature remains unresolved. By quantifying the thermal behaviour of seven functionally-independent enzyme classes (esterase, extradiol dioxygenase, phosphatase, beta-galactosidase, nuclease, transaminase, and aldo-keto reductase) in native proteomes of marine sediment microbiomes from the Irish Sea to the southern Red Sea, we record a significant effect of the mean annual temperature (MAT) on enzyme’s response (R2, 0.51–0.80, p < 0.01 in all cases). Activity and stability profiles of 228 esterases and 5 extradiol dioxygenases from sediment and seawater across 70 locations worldwide (latitude 62.2°S–16°N, MAT –1.4ºC–29.5ºC) validate this thermal pattern. Modelling the esterase phase transition temperature as a measure of structural flexibility, confirm the observed relationship with MAT. Furthermore, when considering temperature variability in sites with non-significantly different MATs, the broadest range of enzyme thermal behaviour and the highest growth plasticity of the enriched heterotrophic bacteria occur in samples with the widest annual thermal variability. These results indicate that temperature-driven enzyme selection shapes microbiome thermal plasticity and that thermal variability finely tunes such processes and should be considered alongside MAT in forecasting microbial community thermal response
Project description:The vertebrate skeleton is mostly composed of three specific cell types: immature chondrocytes (IMM), mature (hypertrophic) chondrocytes (MAT), and osteoblasts (OST). These three cell types are distinct, but they also share the expression of many genes. This overlapping gene expression can be attributed to two transcription factors, SOX9 and RUNX2, which operate near the top of hierarchy of the gene regulatory network (GRN) underlying IMM, MAT, and OST. Sox9 drives IMM differentiation, whereas Runx2 regulates OST differentiation. Importantly, MAT do not form without the function of either Sox9 or Runx2, but little is known about mechanisms of GRN regulation in MAT. During MAT differentiation, the expression of Runx2 increases, and many genes regulated by this transcription such as Spp1, Mef2c, Ibsp, and Alpl are activated. To understand regulatory control of gene expression in mature chondrocytes, ChIP-seq experiments were performed using the mouse chondrogenic cell line ATDC5. These experiments identified in vitro RUNX2 binding sites at different stages of chondrogenesis. RUNX2 appeared to bind in most genes enriched in MAT at both day 3 of differentiation. The ChIP-seq analyses presented here verified the molecular mechanisms predicted here to regulate transcription of the many genomic loci in MAT, proving more insight into regulatory control during cartilage maturation.
Project description:We performed repeated endoscopic colon biopsies of C57BL/6J mice weekly and found that the mesenteric adipose tissue (MAT) was enlarged and it wrapped around the colon at wound sites after 4 cycles of biopsy. On histological view, fibrous bands extended from the intestine into the adjacent MAT, mimicking the fibrosis feature in Crohn’s disease. To investigate the gene signature in the MAT, laser capture microdissection was performed to collect the MAT and associated fibrosis in the repeated biopsy mice and controls. Agilent Microarray was used for the transcriptomic analysis.