A NOVEL HUMAN-MUSCLE FACTOR RELATED TO BUT DISTINCT FROM MYOD1 INDUCES MYOGENIC CONVERSION IN 10T1/2 FIBROBLASTS
A NOVEL HUMAN-MUSCLE FACTOR RELATED TO BUT DISTINCT FROM MYOD1 INDUCES MYOGENIC CONVERSION IN 10T1/2 FIBROBLASTS
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DOI：
10.1002/j.1460-2075.1989.tb03429.x
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发表时间：
1989-03-01
期刊：
影响因子：
11.4
通讯作者：
ARNOLD, HH
中科院分区：
文献类型：
--
作者：
BRAUN, T;BUSCHHAUSENDENKER, G;ARNOLD, HH
通过与小鼠 MyoD1 探针的弱交叉杂交，我们分离出了编码新型人类生肌因子 Myf-5 的 cDNA。核苷酸序列分析和相应基因的鉴定表明，人类Myf-5是一个小基因家族的成员，该家族也含有人类MyoD1的同源物。尽管在结构上与小鼠因子相关，但人 Myf-5 构成了一种不同的蛋白质，但它能够在胚胎 C3H 小鼠 10T1/2“成纤维细胞”中诱导肌源性表型。通过检测几个相似但不同的 cDNA 克隆，进一步表明人类骨骼肌中存在不止一种 MyoD1 样蛋白。人为因素对 10T1/2 细胞的表型转变是通过细胞形成多核合胞体和合成肌节肌球蛋白重链的能力来识别的。此外，Myf-5 在 10T/12 细胞中的瞬时表达导致共转染的肌肉特异性 CAT 报告基因的激活，该基因本身在非肌肉细胞背景中转录沉默。克隆Myf-5的推导氨基酸序列揭示了一个与myc蛋白和果蝇的发育因子高度相似的区域，该区域由无毛菌盾片基因座和twist基因编码。 myc 同源区和前面的碱性氨基酸簇位于较大的序列域中，与小鼠生肌因子 MyoD1 具有很强的相似性。两种蛋白质之间保留了另外两个具有高丝氨酸和苏氨酸含量的短片段。考虑到人 Myf-5 和小鼠 MyoD1 在生肌转化的生物学测定中的相似活性以及不同序列域的片段保守性，表明这三个保守序列区域（包括 myc 同源性）在中胚层细胞的生肌编程中发挥着关键作用。
We have isolated the cDNA encoding a novel human myogenic factor, Myf-5, by weak cross-hybridization to the mouse MyoD1 probe. Nucleotide sequence analysis and the identification of the corresponding gene indicate that human Myf-5 is a member of a small gene family which also contains the human homologue to MyoD1. Although structurally related to the mouse factor, the human Myf-5 constitutes a different protein which nevertheless is capable of inducing the myogenic phenotype in embryonic C3H mouse 10T1/2 ''fibroblasts''. The existence of more than one MyoD1-like protein in human skeletal muscle is further suggested by the detection of several similar but distinct cDNA clones. The phenotypic conversion of 10T1/2 cells by the human factor is recognized by the capacity of the cells to form multinucleated syncytia and synthesize sarcomeric myosin heavy chains. Moreover, transient expression of Myf-5 in 10T/12 cells leads to the activation of a co-transfected muscle-specific CAT reporter gene which by itself is transcriptionally silent in the non-muscle cell background. The deduced amino acid sequence of clone Myf-5 reveals a region which is highly similar to myc proteins and the developmental factors from Drosophila encoded by the achaete scute locus and the twist gene. The myc homology region and a preceding cluster of basic amino acids are located in a larger sequence domain with strong similarity to the mouse myogenic factor MyoD1. Two additional short segments with high serine and threonine content are conserved between the two proteins. Considering the similar activities of human Myf-5 and mouse MyoD1 in the biological assay of myogenic conversion and the segmental conservation of distinct sequence domains, it is suggested that the three conserved sequence regions (including the myc homology) play a critical role in the myogenic programming of mesodermal cells.