ABSTRACT
OBJECTIVE: The aim of this study is to investigate the potential role of DNA methylation in mediating the increased risk of developing type 2 diabetes in offspring of mothers who had diabetes during pregnancy. MATERIALS AND METHODS: Peripheral blood leukocytes were collected from non-diabetic Pima Indians who were either offspring of diabetic mothers (ODM; n=14) or offspring of nondiabetic mothers (ONDM; n=14). The two groups were matched for age, sex, age of mother, and fraction of Pima ethnicity. Differentially methylated regions were determined using a MeDIP-chip assay on an Affymetrix Human Tiling 2.0R Array. Data were analyzed using the model based analysis of tiling arrays (MAT) algorithm, and 4883 regions overlapping with putative promoters, were identified as differentially methylated, having met an empirically derived threshold (nominal p<0.0077). The list of genes with differentially methylated promoters was subjected to KEGG pathway analysis to determine canonical metabolic pathways enriched by these genes. RESULTS: Pathway analysis of genes with differentially methylated promoters identified the top 3 enriched pathways as maturity onset diabetes of the young (MODY), type 2 diabetes, and Notch signaling. Several genes in these pathways are known to affect pancreatic development and insulin secretion. CONCLUSIONS: These findings support the hypothesis that epigenetic changes may increase the risk of type 2 diabetes via an effect on ß-cell function in the offspring of mothers with diabetes during pregnancy.
Subject(s)
DNA Methylation , Diabetes Mellitus, Type 2/genetics , Epigenesis, Genetic/physiology , Gene Expression Regulation, Developmental , Pregnancy in Diabetics , Prenatal Exposure Delayed Effects/genetics , Adolescent , Adult , Child , Female , Gene Expression Profiling , Gene-Environment Interaction , Genome, Human , Humans , Longitudinal Studies , Male , Pregnancy , Uterus/physiology , Young AdultABSTRACT
Auracyanins A and B are two closely similar "blue" copper proteins produced by the filamentous anoxygenic phototrophic bacterium Chloroflexus aurantiacus. Both proteins have a water-soluble 140-residue globular domain, which is preceded in the sequence by an N-terminal tail. The globular domains of auracyanins A and B have sequences that are 38% identical. The sequences of the N-terminal tails, on the other hand, are distinctly different, suggesting that auracyanins A and B occupy different membrane sites and have different functions. The crystal structure of auracyanin A has been solved and refined at 1.85 A resolution. The polypeptide fold is similar to that of auracyanin B (Bond et al. in J Mol Biol 306:47-67, 2001), but the distribution of charged and polar residues on the molecular surface is different. The Cu-site dimensions of the two auracyanins are identical. This is unexpected, since auracyanin A has a shorter polypeptide loop between two of the Cu-binding residues, and the two proteins have significantly different EPR, UV-visible and resonance Raman spectra. The genes for the globular domains of auracyanins A and B have been cloned in a bacterial expression system, enabling purification of large quantities of protein. It is shown that auracyanin A is expressed only when C. aurantiacus cells are grown in light, whereas auracyanin B is expressed under dark as well as light conditions. The inference is that auracyanin A has a function in photosynthesis, and that auracyanin B has a function in aerobic respiration.
Subject(s)
Bacterial Proteins/chemistry , Chloroflexus/chemistry , Metalloproteins/chemistry , Photosynthesis , Amino Acid Sequence , Bacterial Proteins/isolation & purification , Bacterial Proteins/metabolism , Blotting, Western , Chloroflexus/cytology , Chloroflexus/metabolism , Crystallography, X-Ray , Metalloproteins/isolation & purification , Metalloproteins/metabolism , Models, Molecular , Molecular Sequence Data , Polymerase Chain Reaction , Protein Conformation , Recombinant Proteins/chemistry , Recombinant Proteins/isolation & purification , Spectrum Analysis , X-RaysABSTRACT
A new class of bacterial multisubunit membrane-bound electron-transfer complexes has been identified based on biochemical and bioinformatic data. It contains subunits homologous to the three-subunit molybdopterin oxidoreductases and four additional subunits, two of which are c-type cytochromes. The complex was purified from the filamentous anoxygenic phototrophic bacterium Chloroflexus aurantiacus, and putative operons for similar complexes were identified in a wide range of bacteria. In most cases, the presence of the new complex is anticorrelated with the cytochrome bc or bf electron-transfer complex, suggesting that it replaces it functionally. This appears to be a widespread yet previously unrecognized protein complex involved in energy metabolism in bacteria.
