Kherrouche Z, Beuscart A, Huguet C, Flourens A, Moreau-Gachelin F, Stehelin D, Coll J
Institut de Biologie de Lille, UMR 319 CNRS/Institut Pasteur de Lille, France.
Oncogene. 1998 Mar 12;16(10):1357-67. doi: 10.1038/sj.onc.1201650.
Spi-1/PU.1 is a member of the Ets family of transcription factors important in regulation of hematopoiesis. We have isolated a chicken cDNA homologuous to the mammalian Spi-1/PU.1 gene with an open reading frame of 250 amino acids (aa). The chicken Spi-1/PU.1 protein is 14 aa and 16 aa shorter than its human and mouse counterparts but is extremely well conserved with 78.8% and 75.2% identity respectively. The carboxy terminal DNA binding region, or ETS binding domain, is 100% identical to that of human and mouse. Some differences with the mammalian homologues are seen in the N-terminal part of the protein and in the PEST connecting domain. However, the differences are mainly conservative and all the features underlying functional aspects seem preserved. The major discrepancy lies in a 12 aa deletion in an already poorly conserved part of the PEST sequence. Spi-1/PU.1 transcripts were detected at high levels in spleen and Fabricius bursa of chick embryos by Northern blot and in situ hybridization. Our results show that the chicken Spi-1/PU.1 protein behaves like a bonafide Spi-1/PU.1 transcription factor in its DNA binding and transactivating properties.
Spi-1/PU.1是Ets转录因子家族的成员，在造血调控中起重要作用。我们分离出了一个与哺乳动物Spi-1/PU.1基因同源的鸡cDNA，其开放阅读框有250个氨基酸（aa）。鸡的Spi-1/PU.1蛋白分别比人和小鼠的对应蛋白短14个和16个氨基酸，但保守性极高，同源性分别为78.8%和75.2%。其羧基末端DNA结合区域，即ETS结合结构域，与人及小鼠的完全相同。在该蛋白的N端部分和PEST连接结构域与哺乳动物同源物存在一些差异。然而，这些差异主要是保守性的，功能方面的所有特征似乎都得以保留。主要差异在于PEST序列中一个本就保守性较差的部分有12个氨基酸的缺失。通过Northern印迹和原位杂交在鸡胚的脾脏和法氏囊中检测到高水平的Spi-1/PU.1转录本。我们的结果表明，鸡的Spi-1/PU.1蛋白在其DNA结合和反式激活特性方面表现得像一个真正的Spi-1/PU.1转录因子。
