Bours V, Burd P R, Brown K, Villalobos J, Park S, Ryseck R P, Bravo R, Kelly K, Siebenlist U
Laboratory of Immunoregulation, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Bethesda, Maryland 20892.
Mol Cell Biol. 1992 Feb;12(2):685-95. doi: 10.1128/mcb.12.2.685-695.1992.
A Rel-related, mitogen-inducible, kappa B-binding protein has been cloned as an immediate-early activation gene of human peripheral blood T cells. The cDNA has an open reading frame of 900 amino acids capable of encoding a 97-kDa protein. This protein is most similar to the 105-kDa precursor polypeptide of p50-NF-kappa B. Like the 105-kDa precursor, it contains an amino-terminal Rel-related domain of about 300 amino acids and a carboxy-terminal domain containing six full cell cycle or ankyrin repeats. In vitro-translated proteins, truncated downstream of the Rel domain and excluding the repeats, bind kappa B sites. We refer to the kappa B-binding, truncated protein as p50B by analogy with p50-NF-kappa B and to the full-length protein as p97. p50B is able to form heteromeric kappa B-binding complexes with RelB, as well as with p65 and p50, the two subunits of NF-kappa B. Transient-transfection experiments in embryonal carcinoma cells demonstrate a functional cooperation between p50B and RelB or p65 in transactivation of a reporter plasmid dependent on a kappa B site. The data imply the existence of a complex family of NF-kappa B-like transcription factors.
一种与Rel相关的、有丝分裂原诱导的、κB结合蛋白已被克隆为人类外周血T细胞的即刻早期激活基因。该cDNA有一个900个氨基酸的开放阅读框，能够编码一种97 kDa的蛋白质。这种蛋白质与p50-NF-κB的105 kDa前体多肽最为相似。与105 kDa前体一样，它含有一个约300个氨基酸的氨基末端Rel相关结构域和一个羧基末端结构域，该结构域包含六个完整的细胞周期或锚蛋白重复序列。在Rel结构域下游截短且不包括重复序列的体外翻译蛋白能结合κB位点。我们将这种结合κB位点的截短蛋白类比p50-NF-κB称为p50B，将全长蛋白称为p97。p50B能够与RelB以及NF-κB的两个亚基p65和p50形成异源κB结合复合物。胚胎癌细胞中的瞬时转染实验表明，在依赖κB位点报告质粒的反式激活中，p50B与RelB或p65之间存在功能协同作用。这些数据表明存在一个复杂的NF-κB样转录因子家族。
