Project description:To examine gene expression changes duging aging in polyploid and diploid hepatocytes, diploid and polyploid hepatocytes were sorted from young and aged multi-reporter mice and their gene expressions were analyzed by high-throughput RNA sequence.
Project description:Array-based quantitative genome hybridization (aCGH) was performed to quantify gene copy number across the euchromatic portion of the genome of polyploid TGCs relative to embryonic diploid control cells. DNA was prepared from diploid embryonic cells and purified polyploid TGCs, labeled, and hybridized to microarrays. Experiment was performed in two biological replicates.
Project description:Array-based quantitative genome hybridization (aCGH) was performed to quantify gene copy number across the euchromatic portion of the genome of polyploid TGCs relative to embryonic diploid control cells.
Project description:BACKGROUND & AIMS: Thirty to ninety percent of hepatocytes contain whole genome duplications, making it imperative to understand the fates and functions of these polyploid cells and how they affect development of liver disease. An important question is how polyploid cells respond to chronic proliferative demands, which are characteristic of liver diseases, but a challenging situation for cells with multiple genomes. METHODS: To interrogate liver polyploidy, we employed a mouse with reversible ANLN ( Anillin actin binding protein) knockdown that drives hepatocyte polyploidization in a doxycycline inducible fashion. Diethylnitrosamine (DEN) and carbon tetrachloride (CCl4) were used to induce chronic liver damage and hepatocellular carcinoma (HCC). We performed partial hepatectomies to test regeneration and RNA-seq to assess gene expression changes. Lineage tracing was used to rule out repopulation from non-hepatocyte sources. In vivo imaging of mitotic hepatocytes estimated the frequency of aneuploidy during regeneration, and exome sequencing of 54 human cirrhotic nodules was used to quantify aneuploidy. RESULTS: Hepatocytes from mice given chronic CCl4 alone showed significant increases in ploidy. Super-polyploid mice with 97% polyploid hepatocytes, due to induced knockdown of Anln , were almost completely protected from tumorigenesis induced by DEN and chronic CCl4 . The protection was not associated with differences in regenerative capacity, tissue fitness, gene regulation, or mitotic errors. Regenerative contributions from a non-hepatocyte population were ruled out using lineage tracing, confirming that polyploids can replenish tissues during chronic damage. No lagging chromosomes or micronuclei were found in mitotic polyploid cells and there was no evidence of chromosomal copy number variations in 54 nodules, suggesting that aneuploidy is not a common outcome of polyploid cell divisions. CONCLUSION: During chronic injury, polyploid hepatocytes readily divide and regenerate while being buffered from tumor suppressor loss and tumorigenesis. Therapeutic strategies to increase numbers of polypoid hepatocytes could prevent cancer while preserving regeneration.
Project description:Most cells in the liver are polyploid, but the functional role of polyploidy is unknown. We developed orthogonal mouse models to transiently and potently alter liver ploidy. Premature weaning, as well as knockdown of E2f8 or Anln, allowed us to toggle between diploid and polyploid states. While there was no impact of ploidy alterations on liver function, metabolism, or regeneration, more polyploid mice suppressed and more diploid mice accelerated tumorigenesis in mutagen and high-fat induced models. Mechanistically, the diploid state was more susceptible to Cas9-mediated tumor suppressor loss but was similarly susceptible to MYC oncogene activation, indicating that ploidy differentially protected the liver from distinct genomic aberrations.
Project description:we present an atlas of global gene expression as well as the evolutionary divergence covering embryo, endosperm and seed coat development in wheats and their diploid ancestors, providing insights into the evolution of gene expression in embryogenesis and grain development of wheat species.
Project description:Transcriptional change by profiling yeast cells, comparing polyploid S. cerevisiae cells at 1000 generations with ancestral cells. Transcriptional change by profiling yeast cells, comparing both ancestral and evolved cells with diploid cells, stands for control.