Musarella M A, Anson-Cartwright C L, McDowell C, Burghes A H, Coulson S E, Worton R G, Rommens J M
Genetics Department, Hospital for Sick Children, Toronto, Ontario, Canada.
Genomics. 1991 Oct;11(2):263-72. doi: 10.1016/0888-7543(91)90132-x.
A genetic locus (RP3) for X-linked retinitis pigmentosa (XLRP) has been assigned to Xp21 by genetic linkage studies and has been supported by two Xp21 male deletion patients with XLRP. RP3 appears to be the most centromeric of several positioned loci, including chronic granulomatous disease (CGD), McLeod phenotype (XK), and Duchenne muscular dystrophy (DMD). In one patient, BB, the X-chromosome deletion includes RP3 and extends to within the DMD locus. Using a DMD cDNA, the centromeric endpoint of this patient was cloned and used as a starting point for chromosome walking along a normal X chromosome. A single-copy probe, XH1.4, positioned near the centromeric junction but deleted in BB, was used along with a CGD cDNA probe to establish a refined long-range physical map. Both probes recognized a common SfiI fragment of 205 kb. As the CGD gene covers approximately 30-60 kb, the RP3 locus has been restricted to approximately 150-170 kb. A CpG island, potentially marking a new gene, was identified within the SfiI fragment at a position approximately 35 kb from the deletion endpoint in BB.
通过基因连锁研究，已将X连锁视网膜色素变性（XLRP）的一个基因位点（RP3）定位于Xp21，并且得到了两名患有XLRP的Xp21男性缺失患者的支持。RP3似乎是几个定位位点中最靠近着丝粒的，这些位点包括慢性肉芽肿病（CGD）、麦克劳德表型（XK）和杜兴肌营养不良症（DMD）。在一名患者BB中，X染色体缺失包括RP3并延伸至DMD基因座内。利用一个DMD cDNA，克隆了该患者的着丝粒末端，并将其用作沿着正常X染色体进行染色体步移的起点。一个位于着丝粒连接处附近但在BB中缺失的单拷贝探针XH1.4，与一个CGD cDNA探针一起用于建立一个精细的长距离物理图谱。两个探针都识别出一个205 kb的常见SfiI片段。由于CGD基因覆盖约30 - 60 kb，RP3基因座已被限定在约150 - 170 kb范围内。在SfiI片段内，在距离BB中缺失末端约35 kb的位置鉴定出一个潜在标记新基因的CpG岛。
