A genome-wide association study of red-blood cell fatty acids and ratios incorporating dietary covariates: Framingham Heart Study Offspring Cohort
PLOS ONE
Authors: Kalsbeek, Anya; Veenstra, Jenna; Westra, Jason; Disselkoen, Craig; Koch, Kristin; McKenzie, Katelyn A.; O'Bott, Jacob; Vander Woude, Jason; Fischer, Karen; Shearers, Greg C.; Harris, William S.; Tintle, Nathan L.
Abstract
Recent analyses have suggested a strong heritable component to circulating fatty acid (FA) levels; however, only a limited number of genes have been identified which associate with FA levels. In order to expand upon a previous genome wide association study done on participants in the Framingham Heart Study Offspring Cohort and FA levels, we used data from 2,400 of these individuals for whom red blood cell FA profiles, dietary information and genotypes are available, and then conducted a genome-wide evaluation of potential genetic variants associated with 22 FAs and 15 FA ratios, after adjusting for relevant dietary covariates. Our analysis found nine previously identified loci associated with FA levels (FADS, ELOVL2, PCOLCE2, LPCAT3, AGPAT4, NTAN1/PDXDC1, PKD2L1, HBS1L/MYB and RAB3GAP1/MCM6), while identifying four novel loci. The latter include an association between variants in CALN1 (Chromosome 7) and eicosapentaenoic acid (EPA), DHRS4L2 (Chromosome 14) and a FA ratio measuring delta-9-desaturase activity, as well as two loci associated with less well understood proteins. Thus, the inclusion of dietary covariates had a modest impact, helping to uncover four additional loci. While genome-wide association studies continue to uncover additional genes associated with circulating FA levels, much of the heritable risk is yet to be explained, suggesting the potential role of rare genetic variation, epistasis and gene-environment interactions on FA levels as well. Further studies are needed to continue to understand the complex genetic picture of FA metabolism and synthesis.
The interaction between ATRIP and MCM complex is essential for ATRIP chromatin loading and its phosphorylation in mantle cell lymphoma cells
PHARMAZIE
Authors: Nie, Yuling; Lang, Tao
Abstract
Aim: The ATR-interacting protein (ATRIP) is responsible for the recognition of DNA damage-induced structure and regulation of cellular responses to DNA damage and replication stress. The purpose of our study was to identify the underlying mechanism with respect to chromatin loading and phosphorylation of ATRIP in mantle cell lymphoma (MCL). Methods: JeKo cells were used in our study. Differently tagged ATRIP (Myc-, hemaglutinin (HA) or Flag) and minichromosome maintenance (MCM) complex (MCM2, MCM3, MCM5, and MCM6) were transfected into 293T cells. After 48 h, ATRIP-interacting protein was identified by mass spectrometry (MS). Cell fractionation was done to localize proteins inside the cells. Immunoprecipitation (IP) and immunoblot (IB) analysis were used to identify immunoreactive species, and Glutathione S-transferase (GST) pull-down assays were performed to detect protein-protein interaction between ATRIP and MCM complex. After silencing the expression of MCM2 and MCM6 by short hairpin RNA (shRNA), chromatin fraction were analyzed. The expression of ATRIP phosphorylation (pS224-ATRIP) was determined after application of different doses of MCM2 shRNA (0.5 mu g, 1 mu g, and 2.5 mu g). Results: ATRIP directly interacts with MCM2, MCM3, MCM6, and MCM7 in JeKo cells. Downregulation of MCM2 and MCM6 significantly reduced ATRIP chromatin fraction. Downregulation of MCM2 statistically decreased the expression of ATRIP phosphorylation. The expression levels of pS224-ATRIP were regulated by MCM2 shRNA in a dose-dependent manner. Conclusion: Our results suggest that interaction between ATRIP and MCM complex is required for ATRIP chromatin loading and ATRIP phosphorylation.