Molecular cloning and expression of cDNA encoding a murine myeloid leukaemia inhibitory factor (LIF).
Molecular cloning and expression of cDNA encoding a murine myeloid leukaemia inhibitory factor (LIF).
复制标题
编码鼠髓系白血病抑制因子 (LIF) 的 cDNA 的分子克隆和表达。
作者：
D. Gearing;N. Gough;J. A. King;D. Hilton;N. Nicola;R. Simpson;E. Nice;A. Kelso;D. Metcalf
白血病抑制因子(LIF)在体外可诱导M1小鼠髓系白血病细胞向巨噬细胞分化，并抑制其增殖。它不刺激正常祖细胞的增殖，与已知的集落刺激因子明显不同。我们利用与LIF部分氨基酸序列互补的寡核苷酸，从T淋巴细胞cDNA文库中分离出一个LIF克隆。将该基因偶联到酵母表达载体YEpsec1上，并将其导入酵母细胞，可分泌出具有天然LIF生物学特性的分子。LIF的氨基酸序列确定它是一个独特的分子实体，不同于其他已知的造血生长因子。由于LIF是由一个独特的基因编码的，所以在生物化学上可分离的两种形式的LIF可能代表同一基因产物的转录后或翻译后变体。与其他几种造血调节因子不同，LIF在两个被研究的小鼠T淋巴细胞系中结构性地表达了0.8-1kb的LIF mRNA，其丰度不会被刀豆蛋白A刺激而增加。克隆、测序和表达LIF解决了文献中关于能够在体外诱导小鼠髓系白血病细胞分化的因素的几个差异。
Leukaemia inhibitory factor (LIF) can induce macrophage differentiation in M1 murine myeloid leukaemic cells and suppress their proliferation in vitro. It does not stimulate the proliferation of normal progenitor cells and is apparently distinct from known colony‐stimulating factors. We have used oligo‐nucleotides complementary to partial amino acid sequence of LIF to isolate a LIF clone from a T lymphocyte cDNA library. When this cDNA was coupled to a yeast expression vector (YEpsec1) and introduced into yeast cells, a molecule with the biological properties characteristic of native LIF was secreted into the growth medium. The amino acid sequence of LIF established it to be a unique molecular entity, distinct from the other known haemopoietic growth factors. Since LIF is encoded by a unique gene, two biochemically separable forms of LIF probably represent post‐transcriptional or posttranslational variants of the same gene product. In contrast to several other haemopoietic regulators, the 0.8‐ to 1‐kb LIF mRNA was expressed constitutively in two murine T lymphocyte cell lines examined, and its abundance was not enhanced by stimulation with concanavalin A. Cloning, sequencing and expressing LIF has resolved several discrepancies in the literature concerning the identity of factors capable of inducing differentiation of murine myeloid leukaemic cells in vitro.