Dwarfism Research Today is a free monthly online journal that collates and summarizes the latest research about Dwarfism, including details on genetics, diet, mental and motor development.

periostin null mice exhibit dwarfism, incisor enamel defects, and an early-onset periodontal disease-like phenotype.

Rios H, Koushik SV, Wang H, Wang J, Zhou HM, Lindsley A, Rogers R, Chen Z, Maeda M, Kruzynska-Frejtag A, Feng JQ, Conway SJ

Cardiovascular Development Group, Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, 46202, USA.

Periostin was originally identified as an osteoblast-specific factor and is highly expressed in the embryonic periosteum, cardiac valves, placenta, and periodontal ligament as well as in many adult cancerous tissues. To investigate its role during development, we generated mice that lack the periostin gene and replaced the translation start site and first exon with a lacZ reporter gene. Surprisingly, although periostin is widely expressed in many developing organs, periostin-deficient (peri(lacZ)) embryos are grossly normal. Postnatally, however, approximately 14% of the nulls die before weaning and all of the remaining peri(lacZ) nulls are severely growth retarded. Skeletal analysis revealed that trabecular bone in adult homozygous skeletons was sparse, but overall bone growth was unaffected. Furthermore, by 3 months, the nulls develop an early-onset periodontal disease-like phenotype. Unexpectedly, these mice also show a severe incisor enamel defect, although there is no apparent change in ameloblast differentiation. Significantly, placing the peri(lacZ) nulls on a soft diet that alleviated mechanical strain on the periodontal ligament resulted in a partial rescue of both the enamel and periodontal disease-like phenotypes. Combined, these data suggest that a healthy periodontal ligament is required for normal amelogenesis and that periostin is critically required for maintenance of the integrity of the periodontal ligament in response to mechanical stresses.

Published 29 November 2005 in Mol Cell Biol, 25(24): 11131-44.
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