Champliaud M F, Champliaud D, Albalat R, Burgeson R, Magro C, Baden H P
Department of Dermatology, Harvard Medical School, Massachusetts General Hospital, Boston 02129, USA.
J Invest Dermatol. 1998 Mar;110(3):277-81. doi: 10.1046/j.1523-1747.1998.00127.x.
Translocated in liposarcoma (TLS), a member of the Ewing's sarcoma family of RNA binding proteins, is targeted to the product of RNA POL II and functions in nuclear events as well as in nuclear-cytoplasmic transport of mRNA. It has been most extensively studied in cell lines, but was identified in several rat tissues by northern blot analysis, with adipose tissue showing the highest expression followed by whole skin. This paper describes a protein with amino acid sequence homology to TLS that was isolated from bovine tongue epithelium using an affinity column made with an antibody to the cornified envelope precursor sciellin. Using reverse transcriptase polymerase chain reaction technology and total RNA isolated from bovine tongue epithelium, a cDNA was obtained whose nucleotide sequence coded for a protein homologous to human TLS. Nuclear staining in all layers of human epidermis and bovine stratified epithelium was observed with an antibody to TLS, whereas peripheral staining of the upper layers of these tissues was observed with the antibody to sciellin. Cultured cells gave similar results; however, adult tissue required boiling in citrate buffer to unmask antigenic sites before reacting with the TLS antibody. Western blots of extracts of human and bovine keratinocytes using TLS and sciellin antibodies showed that the two proteins shared at least one epitope, but that they were different. TLS was lost from the nucleus following inhibition of RNA POL II activity and the protein was identified in CNBr extracts of purified keratinocytes cornified envelopes by western blot. These results clearly indicate that TLS functions as an RNA binding protein in keratinocytes in vivo and in vitro. Furthermore the sequestration of TLS to the cell envelope may play a role in regulating its nuclear-cytoplasmic transport and effect its role in transcription.
脂肪肉瘤易位蛋白（TLS）是尤因肉瘤家族中RNA结合蛋白的一员，它靶向RNA聚合酶II的产物，在核事件以及mRNA的核质运输中发挥作用。它在细胞系中得到了最广泛的研究，但通过Northern印迹分析在几种大鼠组织中也被鉴定出来，脂肪组织中表达最高，其次是全层皮肤。本文描述了一种与TLS具有氨基酸序列同源性的蛋白质，该蛋白质是使用针对角质化包膜前体丝聚蛋白的抗体制成的亲和柱从牛舌上皮中分离出来的。利用逆转录聚合酶链反应技术和从牛舌上皮中分离的总RNA，获得了一个cDNA，其核苷酸序列编码一种与人TLS同源的蛋白质。用TLS抗体观察到人类表皮各层和牛复层上皮均有核染色，而用丝聚蛋白抗体观察到这些组织上层的外周染色。培养细胞也得到了类似的结果；然而，成人组织在与TLS抗体反应之前需要在柠檬酸盐缓冲液中煮沸以暴露抗原位点。用人和牛角质形成细胞提取物进行的Western印迹分析显示，这两种蛋白质至少有一个共同表位，但它们是不同的。抑制RNA聚合酶II活性后，TLS从细胞核中消失，并且通过Western印迹在纯化的角质形成细胞角质化包膜的溴化氰提取物中鉴定出该蛋白质。这些结果清楚地表明，TLS在体内和体外的角质形成细胞中作为一种RNA结合蛋白发挥作用。此外，TLS在细胞膜上的隔离可能在调节其核质运输以及影响其在转录中的作用方面发挥作用。
