The Study of MafB transcription factor mediating Osteoclast proliferation

我们研究了maf-1的人类同源物的表达，maf-1是maf转录因子家族的一员。利用酵母2杂交系统对mab的同二聚化结构域进行了鉴定，发现其精确边界局限于亮氨酸拉链结构域。采用实时定量RT-PCR方法研究了人几种细胞系中mafB表达的组织分布。为了支持mab表达在巨噬细胞分化中所起的关键作用，我们发现mab在单核细胞U937和THP-1细胞系中表达水平非常高。然而，我们在这里表明，mafB转录不仅局限于髓细胞，也可以在淋巴细胞中检测到，这表明造血过程中的转录可塑性。在生长因子IL-2和IL-4或IL-12存在的情况下，T细胞的激活会下调MafB转录物的水平。综上所述，T细胞激活和白细胞介素（IL-4和IL-12）介导的强增殖信号改变了静息初始CD4^+ T辅助细胞进入体外分化途径时的MafB mRNA水平。

We have studied the expression of a human homologue of mafB (maf-1), a member of the family of large maf transcription factors. The exact boundaries of the homodimerization domain of mafB were characterized by the yeast 2-hybrid system and found to be confined to the leucine zipper domain. Real-time quantitative RT-PCR method was applied to study the tissue distribution of mafB expression in several human cell lines. In support of the suggested key role that mafB expression plays in differentiating macrophages, we found mafB to be expressed at a very high level in monocytic U937 and THP-1 cell lines. However, we show here that mafB transcription is not restricted to myeloid cells but can also be detected in lymphoid cells indicating transcriptional plasticity during hematopoiesis. Activation of T cells in the presence of growth factor IL-2 and IL-4 or IL-12 downregulates the MafB transcript level. In conclusion, strong proliferative signals mediated by T cell activation and interleukines (IL-4 and IL-12) alter the MafB mRNA level when resting naive CD4^+ T helper cells enter the differentiation pathway in vitro.