SUBSTITUTION OF AN ASPARTIC-ACID RESULTS IN CONSTITUTIVE ACTIVATION OF C-KIT RECEPTOR TYROSINE KINASE IN A RAT-TUMOR MAST-CELL LINE RBL-2H3
SUBSTITUTION OF AN ASPARTIC-ACID RESULTS IN CONSTITUTIVE ACTIVATION OF C-KIT RECEPTOR TYROSINE KINASE IN A RAT-TUMOR MAST-CELL LINE RBL-2H3
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DOI：
10.1159/000236870
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发表时间：
1995-04-01
影响因子：
2.8
通讯作者：
KANAKURA, Y
中科院分区：
文献类型：
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作者：
TSUJIMURA, T;FURITSU, T;KANAKURA, Y
C-kit原癌基因编码一种受体酪氨酸激酶，它介导肥大细胞分化、增殖和生存所需的信号。我们已经证明c-kit受体酪氨酸激酶(KIT)在人肥大细胞白血病细胞系(HMC-1)和小鼠肥大细胞瘤细胞系(P-815)中被结构性激活。我们在这里研究了KIT的这种结构性激活是否也发生在大鼠肿瘤肥大细胞系RBL-2H3中，该细胞系经常被用作研究肥大细胞功能的工具。在RBL-2H3细胞中，KIT在酪氨酸上被结构性磷酸化，并且在没有其配体干细胞因子(SCF)自分泌的情况下被激活。测序分析表明，RBL-2H3细胞的c-kit基因发生了点突变，导致密码子817的酪氨酸取代了天冬氨酸。将编码KITTyr817的大鼠野生型c-kit和突变型c-kit基因导入人胚胎肾细胞系(293T)，只有突变型的KITTyr817在酪氨酸上被结构性磷酸化，并在没有姐妹染色单体的情况下被激活，因为在所有的人HMC-1、小鼠P-815和大鼠RBL-2H3细胞中，同一Asp密码子的突变都激活了KIT，并且由于c-KIT信使RNA的反义寡核苷酸的掺入显著抑制了RBL-2H3细胞的增殖，c-KIT基因Asp密码子的激活突变似乎参与了肥大细胞的肿瘤生长。
The c-kit protooncogene encodes a receptor tyrosine kinase that mediates signals required for differentiation, proliferation and survival of mast cells. We have already shown the constitutive activation of c-kit receptor tyrosine kinase (KIT) in a human mast cell leukemia line (HMC-1) and a murine mastocytoma cell line (P-815). We here examined whether such constitutive activation of KIT occurred in the rat tumor mast cell line RBL-2H3 as well, which is frequently used as a tool for studying functions of mast cells. In RBL-2H3 cells, KIT was constitutively phosphorylated on tyrosine and activated in the absence of autocrine production of its ligand, stem cell factor (SCF). Sequencing analysis revealed that one of c-kit genes of RBL-2H3 cells had a point mutation, resulting in amino acid substitution of Tyr for Asp in codon 817. When rat wild-type c-kit cDNA and mutant-type c-kit cDNA encoding KITTyr817 were transfected into cells of a human embryonic kidney cell line (293T), only mutant form KITTyr817 was constitutively phosphorylated on tyrosine and activated in the absence of SCE Since mutations at the same Asp codon constitutively activated KIT in all the human HMC-1, murine P-815, and rat RBL-2H3 cell lines, and since the incorporation of antisense oligonucleotides of c-kit messenger RNA significantly suppressed the proliferation of RBL-2H3 cells, the activating mutations in the Asp codon of the c-kit gene appeared to be involved in neoplastic growth of mast cells.