Meyers-Wallen V N, Bowman L, Acland G M, Palmer V L, Schlafer D, Fajt V
J.A. Baker Institute, College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA.
J Hered. 1995 Sep-Oct;86(5):369-74. doi: 10.1093/oxfordjournals.jhered.a111605.
Present hypotheses indicate that a testis differentiation cascade in mammals is induced by Sry, a gene encoding a DNA binding protein of the high mobility group (HMG) class. In XX sex reversal, individuals lacking a Y chromosome develop testicular tissue. Sry translocation from the Y to the X chromosome has been found in some, but not all, of these individuals. XX sex reversal in the German shorthaired pointer dog may be a model of Sry-negative XX sex reversal in humans. The purposes of this study were to report the familial occurrence of sex reversal and determine whether the conserved Sry HMG box, the region of the Sry protein essential for testis induction, is present in genomic DNA of affected dogs. Canine Sry HMG box sequences were used as primers in polymerase chain reactions. A 104 bp Sry HMG box product was generated from normal males, but not from females or XX sex reversed dogs. Parallel control reactions using hypoxanthine phosphoribosyl transferase primers generated a 177 bp product from all dogs. The pedigree of affected dogs and the absence of Sry HMG box sequences in their genomic DNA suggest that this disorder is due to a mutant autosomal gene in the testis differentiation cascade.
目前的假说表明，哺乳动物的睾丸分化级联是由Sry诱导的，Sry是一种编码高迁移率族（HMG）类DNA结合蛋白的基因。在XX性反转中，缺乏Y染色体的个体发育出睾丸组织。在部分（但并非全部）此类个体中发现了Sry从Y染色体易位到X染色体的情况。德国短毛指示犬的XX性反转可能是人类Sry阴性XX性反转的一个模型。本研究的目的是报告性反转的家族性发生情况，并确定保守的Sry HMG框（Sry蛋白中对睾丸诱导至关重要的区域）是否存在于受影响犬的基因组DNA中。犬Sry HMG框序列被用作聚合酶链反应的引物。正常雄性犬产生了一个104 bp的Sry HMG框产物，但雌性犬或XX性反转犬未产生。使用次黄嘌呤磷酸核糖转移酶引物进行的平行对照反应在所有犬中均产生了一个177 bp的产物。受影响犬的家系及其基因组DNA中不存在Sry HMG框序列表明，这种疾病是由于睾丸分化级联中的一个突变常染色体基因所致。
