Fine-mapping of DNA modifications in the lactase gene region of mice

Transcriptional variation between cells of the same type is a widespread phenomenon which allows for tissues to exhibit regional differences in biological function and disease vulnerability. We analyzed an in vivo transcriptional gradient occurring in enterocytes along the proximal-to-distal axis of the mouse small intestine via bisulfite padlock probe technique. DNA modifications at the lactase gene were investigated in infant and adult mice as well as following lactose-treatment. Overall design: DNA modifications were investigated in mouse enterocytes isolated from mice small intestine dissected into nine equal parts (three sections of duodenum, jejunum and ileum). Analysis was performed on infant (postnatal day 6; n=10, 3-4 per segment) and adult (P60; n=71, 5-6 per segment) mice, or on mice treated with lactose (n=35; 7-9 per segment) or lactose-free milk (n=32; 5-9 per segment).