Siegel J, Brandner G, Hess R D
Department of Virology, Institute for Medical Microbiology and Hygiene, University of Freiburg, D-79104 Freiburg, Germany.
Int J Oncol. 1998 Dec;13(6):1259-62. doi: 10.3892/ijo.13.6.1259.
The C-terminal regions of the human and the murine c-MYC consist of a common conserved sequence, the amino acids (a.a.) 418-439 with one terminal exchange (C438G). The pre-C-terminal region of both proteins, a.a. 408-417, exhibit four exchanges. A commercially available monoclonal antibody, 9E10, raised against the C-terminal a. a. 408-439 of human c-MYC, is declared to recognize specifically and exclusively human c-MYC. However, in an immunofluorescence assay we observed, in addition to the reaction with a human cell line (SV80), reactivity with the murine cell line L929. In analogy, a rabbit polyclonal antiserum raised against a peptide which corresponds to the murine pre-C-terminus of c-MYC, a.a. 408-417, showed also cross-reactivity in immunofluorescence. The immunostaining with both anti-bodies in the human and the murine cell line was competed by the peptide, corresponding to the murine pre-C-terminal a.a. 408-417, whereas the staining of both cell lines with an antiserum raised against the conserved N-terminal region of c-MYC was not competed by this peptide. The cross-reactivity of 9E10 with murine c-MYC was confirmed by Western blot using two additional cell lines. In conclusion, our findings indicate that 9E10 which is generally regarded as specific for human c-MYC cross-reacts with denaturated murine c-MYC.
人类和小鼠c-MYC的C末端区域由一个共同的保守序列组成，即氨基酸（a.a.）418 - 439，其中有一个末端交换（C438G）。两种蛋白质的前C末端区域，即a.a. 408 - 417，有四个交换。一种针对人类c-MYC的C末端a.a. 408 - 439产生的市售单克隆抗体9E10，据称能特异性且唯一地识别人类c-MYC。然而，在免疫荧光测定中，我们观察到，除了与人类细胞系（SV80）反应外，它还与小鼠细胞系L929反应。类似地，一种针对与小鼠c-MYC的前C末端相对应的肽（a.a. 408 - 417）产生的兔多克隆抗血清，在免疫荧光中也显示出交叉反应性。在人类和小鼠细胞系中，用这两种抗体进行的免疫染色都被与小鼠前C末端a.a. 408 - 417相对应的肽所竞争，而用针对c-MYC保守N末端区域产生的抗血清对两种细胞系的染色则不受该肽的竞争。使用另外两种细胞系通过蛋白质印迹法证实了9E10与小鼠c-MYC的交叉反应性。总之，我们的研究结果表明，通常被认为对人类c-MYC具有特异性的9E10与变性的小鼠c-MYC发生交叉反应。
