Project description:Genome-wide DNA methylation profiling of blood duplicate samples (n=128) From Sister Study were used to evaluate how concordance between duplicates were improved at sample level by various methylation preprocessing pipelines
Project description:microRNAs are small, non-coding, single-stranded RNAs between 18-22 nucleotides long that regulate gene expression. Expression of microRNAs is altered in tumor compared to normal tissue; there is some evidence that these changes may be reflected in the serum of cancer cases compared to healthy individuals. This has yet to be examined in a prospective study where samples are collected before diagnosis. We used Affymetrix arrays to examine serum miRNA expression profiles in 410 participants in the Sister Study, a prospective cohort study of 50,884 women. All women in the cohort had never been diagnosed with breast cancer at the time of enrollment.
Project description:microRNAs are small, non-coding, single-stranded RNAs between 18-22 nucleotides long that regulate gene expression. Expression of microRNAs is altered in tumor compared to normal tissue; there is some evidence that these changes may be reflected in the serum of cancer cases compared to healthy individuals. This has yet to be examined in a prospective study where samples are collected before diagnosis. We used Affymetrix arrays to examine serum miRNA expression profiles in 410 participants in the Sister Study, a prospective cohort study of 50,884 women. All women in the cohort had never been diagnosed with breast cancer at the time of enrollment. We compared global miRNA expression patterns in 205 women who subsequently developed breast cancer and 205 women who remained breast cancer-free.
Project description:Polyploidy or whole genome duplication (WGD) provides raw genetic materials for sequence and expression evolution of duplicate genes. However, the mode and tempo of expression divergence between WGD duplicate genes in closely relates species and recurrent allopolyploids are poorly understood. Arabidopsis is a suitable system for testing the hypothesis that duplicate genes increase expression diversity and regulatory networks. In Arabidopsis, WGD occurred more than once prior to the split between Arabidopsis thaliana and Arabidopsis arenosa, and both natural and human-made allotetraploids are available. Comparative genomic hybridization analysis indicated that single-copy and duplicate genes after WGD were well preserved in A. thaliana and A. arenosa. Analysis of gene expression microarrays showed that duplicate genes generally had higher levels of expression divergence between two closely related species than single-copy genes. The proportion of the progenitors' duplicate genes that were nonadditively expressed in the resynthesized and natural allotetraploids was significantly higher than that of single-copy genes. Duplicate genes related to environmental stresses tended to be differentially expressed, and multi-copy duplicate genes were likely to diverge expression between progenitors and in the allotetraploids. Compared to single-copy genes, duplicate genes tend to contain TATA boxes and less DNA methylation in the promoter regions, facilitating transcriptional regulation by binding transcription factors and/or cis-and trans- acting proteins. The data suggest an important role of WGD duplicate genes in modulating diverse and novel gene expression changes in response to external environmental cues as well as internal genetic turmoil such as recurrent polyploidy events.
Project description:Genome wide DNA methylation profiling of saliva samples in Parkinson's disease (PD) patients and PD-free controls. The Illumina Infinium 450k Human DNA methylation Beadchip was used to obtain DNA methylation profiles. Samples included 128 PD patients and 131 controls with saliva DNA.
Project description:Cohesion between sister chromatids depends on the chromosomal cohesin complex and allows the spindle apparatus in mitosis to recognize replicated chromosomes for segregation into daughter cells. Sister chromatid cohesion is established concomitant with DNA replication, and requires the essential Eco1 protein, a replication fork-associated acetyl transferase. The mechanism by which Eco1 establishes sister chromatid cohesion is not known. Here, we show that the cohesin subunit Smc3 is acetylated in an Eco1-dependent manner during S phase to establish sister chromatid cohesion. We isolated spontaneous suppressors of the thermosensitive eco1-1 allele in budding yeast, and identified the suppressor mutations from the hybridization pattern of genomic DNA on oligonucleotide tiling arrays. An acetylation mimicking mutation of a conserved lysine in Smc3 to asparagine (K113N) makes Eco1 dispensable for cell growth, indicating that Smc3 acetylation is Eco1’s only essential function. We identified a second set of eco1-1 suppressor mutations in the budding yeast ortholog of the cohesin regulator Wapl (Wpl1/Rad61). Wapl destabilizes cohesin on chromosomes, and Eco1-dependent Smc3 acetylation during S-phase might render cohesin resistant to Wapl. Our results clarify the role of Eco1 in the establishment of sister chromatid cohesion, and suggest that Eco1 modifies cohesin to stabilize an Eco1-independent cohesion establishment reaction.