Shanmugam V, Chapman V M, Sell K W, Saha B K
Department of Pathology, Emory University School of Medicine, Atlanta, Georgia 30329, USA.
Biochem Genet. 1996 Feb;34(1-2):17-29. doi: 10.1007/BF02396237.
The X-linked immunodeficiency (Xid) in CBA/N mice serves as a model for the X-linked agammaglobulinemia (XLA) syndrome in man. X-chromosome inactivation in F1 heterozygotes derived from CBA/N (Xxid/Xxid) and B6.Pgk-1a (X+/Y) was investigated by monitoring the methylation status of the individual Pgk-1 alleles, Pgk-1b and Pgk-1a, respectively, using a novel Tth111I RFLP. Results indicate that in circulating B lymphocytes of female heterozygotes, only the X chromosomes carrying the normal alleles (X+) are active (nonrandom inactivation of the X chromosome), whereas in non-B cells both the X chromosomes (X+ and Xxid) are active (random inactivation of the X chromosome). These results were further confirmed by direct evaluation of transcription of the Btk gene, the gene mutated both in Xid and in XLA.
CBA/N小鼠中的X连锁免疫缺陷（Xid）可作为人类X连锁无丙种球蛋白血症（XLA）综合征的模型。通过使用一种新型的Tth111I限制性片段长度多态性（RFLP）分别监测单个磷酸甘油酸激酶-1（Pgk-1）等位基因Pgk-1b和Pgk-1a的甲基化状态，研究了源自CBA/N（Xxid/Xxid）和B6.Pgk-1a（X+/Y）的F1杂合子中的X染色体失活情况。结果表明，在雌性杂合子的循环B淋巴细胞中，只有携带正常等位基因（X+）的X染色体是活跃的（X染色体的非随机失活），而在非B细胞中，两条X染色体（X+和Xxid）都是活跃的（X染色体的随机失活）。通过直接评估布鲁顿酪氨酸激酶（Btk）基因的转录进一步证实了这些结果，该基因在Xid和XLA中均发生突变。
