Lo K, Landau N R, Smale S T
Howard Hughes Medical Institute, Molecular Biology Institute, UCLA School of Medicine 90024.
Mol Cell Biol. 1991 Oct;11(10):5229-43. doi: 10.1128/mcb.11.10.5229-5243.1991.
We have studied transcriptional control of the murine terminal deoxynucleotidyltransferase (TdT) gene, which is activated specifically in immature B and T lymphocytes. This analysis has led to the identification and purification of a 50-kDa sequence-specific DNA-binding protein, LyF-1, that interacts with the approximate consensus sequence PyPyTGGGAGPu and is enriched in cells at most stages of B- and T-cell differentiation. LyF-1 binds tightly to an element in the TdT promoter that we show is required for transcription in lymphocytes. LyF-1 also interacts with an element in the immunoglobulin mu enhancer, called microB, that was recently shown to be important for lymphocyte-specific enhancer activity. Moreover, LyF-1 binds to the promoters for the lymphocyte-specific genes lambda 5, VpreB, and lck, all of which we speculate have additional features in common with the TdT promoter. Thus, LyF-1 may be a general transcriptional activator for genes whose expression is restricted to the B- and/or T-lymphocyte lineages.
我们研究了小鼠末端脱氧核苷酸转移酶（TdT）基因的转录调控，该基因在未成熟的B淋巴细胞和T淋巴细胞中特异性激活。这项分析导致了一种50 kDa序列特异性DNA结合蛋白LyF-1的鉴定和纯化，该蛋白与近似共有序列PyPyTGGGAGPu相互作用，并在B细胞和T细胞分化的大多数阶段的细胞中富集。LyF-1紧密结合TdT启动子中的一个元件，我们证明该元件是淋巴细胞中转录所必需的。LyF-1还与免疫球蛋白μ增强子中的一个元件相互作用，该元件称为microB，最近被证明对淋巴细胞特异性增强子活性很重要。此外，LyF-1与淋巴细胞特异性基因lambda 5、VpreB和lck的启动子结合，我们推测所有这些基因与TdT启动子还有其他共同特征。因此，LyF-1可能是其表达仅限于B淋巴细胞和/或T淋巴细胞谱系的基因的一般转录激活因子。
