Expression of the Mutant (1735T-DEL) Tissue-Nonspecific Alkaline Phosphatase Gene from Hypophosphatasia Patients

• DOI: 10.1359/jbmr.1998.13.12.1827
• Publication Date: 2006-04-26T23:51:59Z
• Authors: Masae Dr. Goseki-...; Hideo Orimo; Tadahiro Iimura; Hidetaka Miyazaki; Kimimitsu Oda; Hisanobu Shibata; Masaki Yanagishita; Yuzo Takagi; Hisashi Watanabe; Takashi Shimada; Shinichiro Oida
• Keywords: Hypophosphatasia; Phosphoric monoester hydrolases

Abstract Hypophosphatasia (HOPS) is an inherited disorder characterized by defects in skeletal mineralization due to the deficiency of tissue-nonspecific alkaline phosphatase (TNSALP). To date, various mutations TNSALP gene have been identified. Especially, a deletion T at position 1735 (1735T-del) located exon 12 has detected three genetically unrelated Japanese patients, which seems be one hot spots among causative HOPS patients. 1735T-del causes frame shift downstream from codon 503 (Leu), and consequently normal termination 508 eliminated. Since new inframe appears 588 mutant DNA, resultant protein expected 80 additional amino acids. Expression using COS-1 cells demonstrated that translated had undetectable ALP activity, its molecule size was larger than normal, as expected. Interestingly, immunoprecipitation study patients' sera antibody against revealed abnormal corresponded mutated expressed cells, suggesting made The detection transfected with immunofluorescent method exhibited only faint signal on cell surface, but intense intracellular fluorescence after permeabilization.