A novel mutation at the JK locus causing Jknull phenotype in a Chinese family
Urea transporters are a group of proteins that facilitate urea movement across biological membranes. Kidd blood group (JK antigen) and urea transporter of human erythrocytes are carried by the same protein UT-B. To investigate the molecular basis of the Jknull phenotype in the Chinese population, blood samples from Chinese individuals were screened using the 2 mol/L urea solution hemolysis test. Urea and water permeability of erythrocytes membrane was measured by stopped-flow light scattering. Genomic DNA was extracted from lymphocytes. UT-B gene of Jknull's family was analyzed using genomic PCR by primers designed to cover sequences of all exons and exon-intron boundaries in human UT-B gene. One Jknull subject was found from twenty thousand screened Chinese individuals, and it was confirmed that this individual did not express the erythrocyte urea transporter. Genomic sequence analysis of the Jknull individual showed that there were two point mutations, G→C, which is novel, and G→A, at the 3(-acceptor splice site (AG) of intron 5 of UT-B gene. Exon 6 is spliced out in the UT-B transcript due to either of these mutations. Water permeability in Jknull erythrocytes (Pf, ~0.00037 cm/s) was significantly lower than that in normal erythrocytes (Pf, ~0.00062 cm/s) after HgCl2 incubation, providing evidence for UT-B facilitated water transport in human erythrocytes.
作 者： MENG Yan ZHOU Xueyan LI Yang ZHAO Dan LIANG Shuyuan ZHAO Xuejian YANG Baoxue 作者单位： MENG Yan,LI Yang,ZHAO Dan,ZHAO Xuejian(Department of Pathophysiology, School of Medical Science, Jilin University, Changchun 130021, China)ZHOU Xueyan,LIANG Shuyuan(The Third Hospital of Jilin University, Changchun 130031, China)
YANG Baoxue(Department of Pathophysiology, School of Medical Science, Jilin University, Changchun 130021, China;Departments of Medicine, University of California, San Francisco, CA, 94143-0521, USA)
刊 名： 中国科学C辑（英文版） SCI 英文刊名： SCIENCE IN CHINA (LIFE SCIENCES) 年，卷(期)： 2005 48(6) 分类号： Q3 关键词： urea transporter JK antigen urea erythrocyte water permeability