Fumagalli S, Volpi L, Rossi D, Larizza L
Department of Biology and Genetics, Faculty of Medicine, University of Milan, Italy.
Int J Cancer. 1992 Sep 30;52(3):478-82. doi: 10.1002/ijc.2910520324.
The expression of proto-oncogenes involved in myelomonocytic differentiation was studied in 3 metastatic murine lympho-macrophage hybrids (ESb, EbF1, EbF2-C4) which display several antigenic and functional macrophage properties. Constitutive expressions of fos and fesmRNA, which were not detectable in the weakly metastatic parent lymphoma (Eb), was shown in all the proliferating hybrid lines. By contrast, c-myc and c-myc expressions were shared by the tumor parent and the hybrids. The c-fos transcripts observed in the hybrids were atypical in size, 2.3 kb, but standard 2.2-kb transcripts could be detected in serum-induced cells, even in the non-expressing Eb lymphoma. The kinetics of the induced fos mRNA was found to conform to the features reported in the literature for a large variety of cells. No structural alteration of the c-fos gene was detected by Southern analysis. PCR amplification of the 2.3- and 2.2-kb fos mRNA showed that they are identical in size in both the coding and the 3' untranscribed region. A longer poly A tail is thought to account for the additional 100 bp in the 2.3-kb fos mRNA, as both the 2.3- and 2.2-kb transcripts attain the same size following de-adenylation.
在3种转移性小鼠淋巴细胞 - 巨噬细胞杂交细胞系（ESb、EbF1、EbF2 - C4）中研究了参与骨髓单核细胞分化的原癌基因的表达，这些杂交细胞系表现出多种抗原性和功能性巨噬细胞特性。在所有增殖的杂交细胞系中均显示出fos和fesmRNA的组成型表达，而在低转移性亲代淋巴瘤（Eb）中未检测到这种表达。相比之下，肿瘤亲代和杂交细胞系均有c - myc表达。在杂交细胞系中观察到的c - fos转录本大小非典型，为2.3 kb，但即使在不表达的Eb淋巴瘤中，在血清诱导的细胞中也可检测到标准的2.2 kb转录本。发现诱导的fos mRNA的动力学符合文献中报道的多种细胞的特征。通过Southern分析未检测到c - fos基因的结构改变。对2.3 kb和2.2 kb的fos mRNA进行PCR扩增表明，它们在编码区和3'非转录区的大小相同。据认为，2.3 kb的fos mRNA中额外的100 bp是由于poly A尾更长，因为在去腺苷酸化后，2.3 kb和2.2 kb的转录本大小相同。
