Blackwell T K, Kretzner L, Blackwood E M, Eisenman R N, Weintraub H
Division of Basic Sciences, Fred Hutchinson Cancer Research Center, Seattle, WA 98104.
Science. 1990 Nov 23;250(4984):1149-51. doi: 10.1126/science.2251503.
While it has been known for some time that the c-Myc protein binds to random DNA sequences, no sequence-specific binding activity has been detected. At its carboxyl terminus, c-Myc contains a basic--helix-loop-helix (bHLH) motif, which is important for dimerization and specific DNA binding, as demonstrated for other bHLH protein family members. Of those studied, most bHLH proteins bind to sites that contain a CA- -TG consensus. In this study, the technique of selected and amplified binding-sequence (SAAB) imprinting was used to identify a DNA sequence that was recognized by c-Myc. A purified carboxyl-terminal fragment of human c-Myc that contained the bHLH domain bound in vitro in a sequence-specific manner to the sequence, CACGTG. These results suggest that some of the biological functions of Myc family proteins are accomplished by sequence-specific DNA binding that is mediated by the carboxyl-terminal region of the protein.
虽然人们早就知道c-Myc蛋白能与随机DNA序列结合，但尚未检测到序列特异性结合活性。在其羧基末端，c-Myc含有一个碱性-螺旋-环-螺旋（bHLH）基序，正如其他bHLH蛋白家族成员所表明的那样，该基序对于二聚化和特异性DNA结合很重要。在已研究的那些蛋白中，大多数bHLH蛋白与含有CA--TG共有序列的位点结合。在本研究中，采用了选择和扩增结合序列（SAAB）印记技术来鉴定c-Myc识别的DNA序列。含有bHLH结构域的人c-Myc纯化羧基末端片段在体外以序列特异性方式与序列CACGTG结合。这些结果表明，Myc家族蛋白的一些生物学功能是通过由该蛋白羧基末端区域介导的序列特异性DNA结合来实现的。
