Jones M H, Furlong R A, Burkin H, Chalmers I J, Brown G M, Khwaja O, Affara N A
University of Cambridge, Department of Pathology, UK.
Hum Mol Genet. 1996 Nov;5(11):1695-701. doi: 10.1093/hmg/5.11.1695.
EST 221 derived from human adult testis detects homology to the Drosophila fat facets gene (fat) and has related sequences on both the X and Y chromosomes mapping to Xp11.4 and Yq11.2 respectively. These two loci have been termed DFFRX and DFFRY for Drosophila fat facets related X and Y. The major transcript detected by EST 221 is-8 kb in size and is expressed widely in a range of 16 human adult tissues. RT-PCR analysis of 13 different human embryonic tissues with primers specific for the X and Y sequences demonstrates that both loci are expressed in developing tissues and quantitative RT-PCR of lymphoblastoid cell lines carrying different numbers of X chromosomes reveals that the X-linked gene escapes X-inactivation. The amino acid sequence (2547 residues) of the complete open reading frame of the X gene has 44% identity and 88% similarity to the Drosophila sequence and contains the conserved Cys and His domains characteristic of deubiquitinating enzymes, suggesting its biochemical function may be the hydrolysis of ubiquitin from protein-ubiquitin conjugates. The requirement of faf for normal oocyte development in Drosophila combined with the map location and escape from X-inactivation of DFFRX raises the possibility that the human homologue plays a role in the defects of oocyte proliferation and subsequent gonadal degeneration found in Turner syndrome.
源自人类成年睾丸的EST 221与果蝇的脂肪小面基因（fat）存在同源性，并且在X和Y染色体上都有相关序列，分别定位于Xp11.4和Yq11.2。这两个基因座分别被称为DFFRX和DFFRY，代表与果蝇脂肪小面相关的X和Y基因座。EST 221检测到的主要转录本大小约为8 kb，在16种人类成年组织中广泛表达。用针对X和Y序列的特异性引物对13种不同的人类胚胎组织进行RT-PCR分析表明，这两个基因座在发育中的组织中均有表达，对携带不同数量X染色体的淋巴母细胞系进行定量RT-PCR显示，X连锁基因逃避X染色体失活。X基因完整开放阅读框的氨基酸序列（2547个残基）与果蝇序列有44%的同一性和88%的相似性，并包含去泛素化酶特有的保守半胱氨酸和组氨酸结构域，表明其生化功能可能是从蛋白质-泛素缀合物中水解泛素。果蝇中faf对正常卵母细胞发育的需求，结合DFFRX的图谱定位和逃避X染色体失活的特性，增加了人类同源物在特纳综合征中卵母细胞增殖缺陷和随后性腺退化中起作用的可能性。
