The Study of MafB transcription factor mediating Osteoclast proliferation

我们已经研究了人类同源物mafB（maf-1），大maf转录因子家族的成员的表达。酵母2-杂交系统的特点是准确的边界的同源二聚化结构域的mafB被发现局限于亮氨酸拉链结构域。应用实时荧光定量RT-PCR方法研究了mafB在几种人类细胞系中的组织分布。为了支持mafB表达在分化巨噬细胞中所起的关键作用，我们发现mafB在单核细胞U937和THP-1细胞系中以非常高的水平表达。然而，我们在这里表明，mafB转录并不限于骨髓细胞，但也可以检测到淋巴细胞，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存在下T细胞的活化下调MafB转录物水平。总之，当静止的初始CD 4 ^+ T辅助细胞进入体外分化途径时，由T细胞活化和白细胞介素（IL-4和IL-12）介导的强增殖信号改变了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.