Didier D K, Schiffenbauer J, Woulfe S L, Zacheis M, Schwartz B D
Howard Hughes Medical Institute Laboratories, Saint Louis, MO.
Proc Natl Acad Sci U S A. 1988 Oct;85(19):7322-6. doi: 10.1073/pnas.85.19.7322.
The expression of HLA class II genes is regulated by a series of cis-acting elements and trans-acting factors. Several cis-acting elements have been identified and have been termed the Z box, X box, Y box, octamer, and "TATA" box. The Y box contains an inverted CCAAT box. By probing a phage lambda gt11 library with double-stranded oligonucleotides, we have directly isolated a cDNA encoding a Y box-binding protein designated YB-1. YB-1 binding has an absolute requirement for the CCAAT box and relative specificity for the Y box. It has a Mr of 35,414, contains 18% basic residues, and contains putative nuclear localization signals. An inverse correlation of YB-1 and HLA-DR beta chain mRNA levels suggests that YB-1 is a negative regulatory factor.
HLA II类基因的表达受一系列顺式作用元件和反式作用因子调控。已鉴定出几种顺式作用元件，分别称为Z盒、X盒、Y盒、八聚体和“TATA”盒。Y盒含有一个反向CCAAT盒。通过用双链寡核苷酸探测噬菌体λgt11文库，我们直接分离出了一个编码Y盒结合蛋白（命名为YB-1）的cDNA。YB-1的结合对CCAAT盒有绝对需求，对Y盒有相对特异性。它的分子量为35414，含有18%的碱性残基，并含有假定的核定位信号。YB-1与HLA-DRβ链mRNA水平呈负相关，提示YB-1是一种负调控因子。
