Nakajima T, Ichii S, Furuyama J, Tamaoki T, Hashimoto T
Department of Genetics, Hyogo College of Medicine, Japan.
Life Sci. 1996;58(9):761-8. doi: 10.1016/0024-3205(95)02354-2.
The Fas antigen (Fas/APO-1/CD95) has been shown to induce apoptosis when bound to a monoclonal anti-Fas antibody or Fas ligands. Recently, a new soluble human Fas isoform which lacks the transmembrane domain due to alternative splicing has been isolated; however, no mouse Fas isoforms have been reported so far. Analysis of Fas transcripts by RT-PCR detected no Fas transcripts corresponding to the human soluble Fas isoform in mouse thymus, spleen and liver. However, we detected a new isoform with a 117-bp deletion in the second exon in various mouse tissues and cell lines. This isoform, termed truncated Fas (T-Fas), can be generated by alternative splicing and lacks the N-terminal portion of the extracellular domain just after the signal sequence. Since the deletion involves the first cysteine-rich motif believed to be necessary for binding to the Fas ligand, the T-Fas protein may lack the ability to induce apoptosis. The expression of T-Fas relative to that of the normal Fas varies considerably among mouse tissues and cell lines, suggesting preferential transcription of the T-Fas isoform in certain cell types.
Fas抗原（Fas/APO-1/CD95）已被证明，当与单克隆抗Fas抗体或Fas配体结合时可诱导细胞凋亡。最近，一种因可变剪接而缺乏跨膜结构域的新型可溶性人Fas异构体已被分离出来；然而，迄今为止尚未报道有小鼠Fas异构体。通过逆转录聚合酶链反应（RT-PCR）分析Fas转录本，在小鼠胸腺、脾脏和肝脏中未检测到与人类可溶性Fas异构体相对应的Fas转录本。然而，我们在各种小鼠组织和细胞系中检测到一种在第二个外显子中有117个碱基对缺失的新异构体。这种异构体被称为截短型Fas（T-Fas），可通过可变剪接产生，并且在信号序列之后缺少细胞外结构域的N端部分。由于该缺失涉及被认为是与Fas配体结合所必需的第一个富含半胱氨酸的基序，T-Fas蛋白可能缺乏诱导细胞凋亡的能力。T-Fas相对于正常Fas的表达在小鼠组织和细胞系中差异很大，这表明T-Fas异构体在某些细胞类型中优先转录。
