ABSTRACT
Genetic associations for keratoconus could be useful for understanding disease pathogenesis and discovering biomarkers for early detection of the disease. We conducted a systematic review and meta-analysis to summarize all reported genetic associations for the disease. We searched in the MEDLINE, Embase, Web of Science, and HuGENET databases for genetic studies of keratoconus published from 1950 to June 2016. The summary odds ratio and 95% confidence intervals of all polymorphisms were estimated using the random-effect model. Among 639 reports that were retrieved, 24 fulfilled required criteria as eligible studies for meta-analysis, involving a total of 53 polymorphisms in 28 genes/loci. Results of our meta-analysis lead to the prioritization of 8 single-nucleotide polymorphisms (SNPs) in 6 genes/loci for keratoconus in Whites. Of them 5 genes/loci were originally detected in genome-wide association studies, including FOXO1 (rs2721051, P = 5.6 × 10-11), RXRA-COL5A1 (rs1536482, P = 2.5 × 10-9), FNDC3B (rs4894535, P = 1.4 × 10-8), IMMP2L (rs757219, P = 6.1 × 10-7; rs214884, P = 2.3 × 10-5), and BANP-ZNF469 (rs9938149, P = 1.3 × 10-5). The gene COL4A4 (rs2229813, P = 1.3 × 10-12; rs2228557, P = 4.5 × 10-7) was identified in previous candidate gene studies. We also found SNPs in 10 genes/loci that had a summary P value < 0.05. Sensitivity analysis indicated that the results were robust. Replication studies and understanding the roles of these genes in keratoconus are warranted.
Subject(s)
Genetic Association Studies/methods , Genetic Markers , Keratoconus/genetics , Polymorphism, Single Nucleotide , Adolescent , Adult , Aged , Collagen Type IV/genetics , Collagen Type V/genetics , Early Diagnosis , Endopeptidases/genetics , Fibronectins/genetics , Forkhead Box Protein O1/genetics , Genetic Predisposition to Disease , Humans , Middle Aged , Odds Ratio , Young AdultABSTRACT
DNA ligase catalyzes the closure of single-strand nicks in double-stranded DNA that arise during replication and recombination. Inhibition of bacterial ligase is expected to cause chromosome degradation and cell death, making it an attractive target for new antibacterials. The prototypical bacterial ligase couples the hydrolysis of NAD(+) to phosphodiester bond formation between an adjacent 3'OH and 5'-terminal phosphate of nicked duplex DNA. The first step is the reversible formation of a ligase-adenylate from the reaction between apoenzyme and NAD(+). Inhibitors that compete with NAD(+) are expected to be bacterial specific because eukaryotic DNA ligases use ATP and differ in the sequence composition of their adenylation domain. We report here a high-throughput assay that measures the adenylation reaction specifically by monitoring ligase-AMP formation via scintillation proximity technologies. Escherichia coli DNA ligase was biotinylated in vivo; after reaction with radiolabeled NAD(+), ligase-[(3)H]AMP could be captured onto the streptavidin-coated surface of the solid scintillant. The method was ideal for high-throughput screening because it required minimal manipulations and generated a robust signal with minimal scatter. Certain adenosine analogs were found to inhibit the adenylation assay and had similar potency of inhibition in a DNA ligation assay.
