Xin X Q, Nelson C, Collins L, Dorshkind K
Department of Biochemistry, University of California, Riverside 92521-0121.
J Immunol. 1993 Nov 15;151(10):5398-407.
The DNA-binding factors encoded by the E2A gene, which include the basic helix-loop-helix proteins E12 and E47, are thought to regulate Ig gene expression. In the rat these factors are products of the Pan locus and are referred to as Pan-2 and Pan-1, respectively. To determine when during B cell differentiation Pan (E2A) DNA-binding proteins are first expressed, cells from a newly developed rat long term lymphoid bone marrow culture system were analyzed molecularly and phenotypically using a newly defined anti-Pan mAb. The data indicate that Pan-expressing cells appear in B cell progenitors before the appearance of the CD45R B lineage-associated Ag or microH chain protein. The results also indicate that Pan proteins are present in cells that had undergone D-JH rearrangements. Finally, although Pan (E2A) proteins are present in myeloid precursors, expression is extinguished as differentiation into mature myeloid cells occurs.
E2A基因编码的DNA结合因子，包括碱性螺旋-环-螺旋蛋白E12和E47，被认为可调节Ig基因表达。在大鼠中，这些因子是Pan基因座的产物，分别被称为Pan-2和Pan-1。为了确定在B细胞分化过程中Pan（E2A）DNA结合蛋白首次表达的时间，使用新定义的抗Pan单克隆抗体对来自新建立的大鼠长期淋巴样骨髓培养系统的细胞进行了分子和表型分析。数据表明，表达Pan的细胞在CD45R B谱系相关抗原或μ重链蛋白出现之前出现在B细胞祖细胞中。结果还表明，Pan蛋白存在于经历了D-JH重排的细胞中。最后，尽管Pan（E2A）蛋白存在于髓系前体细胞中，但随着向成熟髓系细胞的分化，其表达消失。
