Age-dependent biologic response to orthodontic forces.

Introduction: Orthodontic tooth movement results from increased inflammation and osteoclast activation. Since patients of all ages now routinely seek orthodontics treatment, we investigated whether age-dependent biologic responses to orthodontic force correlate with the rate of tooth movement.

Methods: We studied 18 healthy subjects, adolescents (11-14 years) and adults (21-45 years), with Class II Division 1 malocclusion requiring 4 first premolar extractions.

Promoter-proximal introns in Arabidopsis thaliana are enriched in dispersed signals that elevate gene expression.

Introns that elevate mRNA accumulation have been found in a wide range of eukaryotes. However, not all introns affect gene expression, and direct testing is currently the only way to identify stimulatory introns. Our genome-wide analysis in Arabidopsis thaliana revealed that promoter-proximal introns as a group are compositionally distinct from distal introns and that the degree to which an individual intron matches the promoter-proximal intron profile is a strong predictor of its ability to increase expression.