Altered ultrastructure, density and cathepsin K expression in bone of female muscarinic acetylcholine receptor M3 knockout mice.

High frequency of osteoporosis is found in postmenopausal women where several molecular components were identified to be involved in bone loss that subsequently leads to an increased fracture risk. Bone loss has already been determined in male mice with gene deficiency of muscarinic acetylcholine receptor M3 (M3R-KO). Here we asked whether bone properties of female 16-week old M3R-KO present similarities to osteoporotic bone loss by means of biomechanical, radiological, electron microscopic, cell- and molecular biological methods.

Small changes in bone structure of female α7 nicotinic acetylcholine receptor knockout mice.

Background: Recently, analysis of bone from knockout mice identified muscarinic acetylcholine receptor subtype M3 (mAChR M3) and nicotinic acetylcholine receptor (nAChR) subunit α2 as positive regulator of bone mass accrual whereas of male mice deficient for α7-nAChR (α7KO) did not reveal impact in regulation of bone remodeling. Since female sex hormones are involved in fair coordination of osteoblast bone formation and osteoclast bone degradation we assigned the current study to analyze bone strength, composition and microarchitecture of female α7KO compared to their corresponding wild-type mice (α7WT).

Methods: Vertebrae and long bones of female 16-week-old α7KO (n = 10) and α7WT (n = 8) were extracted and analyzed by means of histological, radiological, biomechanical, cell- and molecular methods as well as time of flight secondary ion mass spectrometry (ToF-SIMS) and transmission electron microscopy (TEM).

A functional insulator screen identifies NURF and dREAM components to be required for enhancer-blocking.

Chromatin insulators of higher eukaryotes functionally divide the genome into active and inactive domains. Furthermore, insulators regulate enhancer/promoter communication, which is evident from the Drosophila bithorax locus in which a multitude of regulatory elements control segment specific gene activity. Centrosomal protein 190 (CP190) is targeted to insulators by CTCF or other insulator DNA-binding factors.