Cloning and characterization of three PHEX homologues in Drosophila
Cloning and characterization of three PHEX homologues in Drosophila
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DOI：
10.1007/s00774-003-0440-8
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发表时间：
2004-01-01
影响因子：
3.3
通讯作者：
Miyamoto, KI
中科院分区：
文献类型：
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作者：
Ito, M;Akai, E;Miyamoto, KI
PHEX（X染色体上与内肽酶同源的磷酸盐调节基因）的失活突变和/或缺失是导致人类X连锁低磷血症性佝偻病的原因。本研究通过果蝇cDNA文库和表达序列标签（EST）数据库的筛选，获得了3个果蝇PHEX同源基因（dPHEX-1，-2，-3）。涉及基序II：（456）WMXXXTKXXAXXK（468）（根据人PHEX编号）、基序VI：（WW 603）-W-602和基序VIII：（CXLW 749）-C-746的结构区域在dPHEX家族中是保守的。锌配位基序（HEFTH和GENIADNGG）在dPHEX家族中也是保守的。所有三个dPHEX基因表达在果蝇发育的各个阶段。缺磷抑制了dPHEX-1的表达，但对dPHEX-2和dPHEX-3的表达没有影响。原位杂交结果显示dPHEX-1和dPHEX-2在脑组织中普遍存在，而dPHEX-3在脑组织中高度表达。在亚细胞定位分析中，dPHEX-1定位于细胞内细胞器，dPHEX-3主要定位于果蝇胚胎S2细胞的质膜。纯合性的dPHEX-1突变，转座子插入dPHEX-1启动子区，是完全致命的早期胚胎发育阶段。目前的研究表明，三个同源物可能参与果蝇的磷酸盐稳态。
Inactivating mutations and/or deletions of PHEX (Phosphate-regulating gene with Homologies to Endopeptidase on the X chromosome) are responsible for X-linked hypophosphatemic rickets in humans. In the present study, three Drosophila PHEX homologues (dPHEX-1, -2, -3) were isolated by the screening of a Drosophila cDNA library and expressed sequence tag (EST) database. The structural region involving motif II: (456)WMXXXTKXXAXXK(468) (numbered according to human PHEX), motif VI: (WW603)-W-602, and motif VIII: (CXLW749)-C-746 was conserved in the dPHEX family. Zinc-coordinating motifs (HEFTH and GENIADNGG) were also conserved in the dPHEX family. All three dPHEX genes were expressed during all stages of Drosophila development. The expression of dPHEX-1 was suppressed by dietary phosphate deprivation, but the expression of dPHEX-2 and that of dPHEX-3 were not affected. In-situ hybridization showed a ubiquitous distribution of dPHEX-1 and dPHEX-2, while dPHEX-3 was highly expressed in the larval brain. In an analysis of subcellular localization, dPHEX-1 was localized to intracellular organelles and dPHEX-3 was localized predominately in the plasma membrane of Drosophila embryonic S2 cells. Homozygosity of a dPHEX-1 mutation, a transposon insertion in the dPHEX-1 promoter region, was completely lethal at an early stage of embryonic development. The present study indicates that three homologues are likely involved in the phosphate homeostasis of Drosophila.