Subcellular Transport of EKLF and Switch-On of Murine Adult βmaj Globin Gene Transcription
Subcellular Transport of EKLF and Switch-On of Murine Adult βmaj Globin Gene Transcription
复制标题
EKLF 的亚细胞转运和小鼠成体 βmaj 球蛋白基因转录的开启
作者：
Y. Shyu;Tung;S. Wen;Hsin;W. Hsiao;Xin Chen;Jaulang Hwang;Che
红系克鲁类β珠蛋白样因子（EKLF）是哺乳动物β珠蛋白基因转换的关键转录因子，它通过锌指与启动子的结合特异性激活成人β珠蛋白基因的转录。在小鼠中，尽管EKLF在整个红系发育过程中表达，但EKLF仅在胚胎第10.5天（E10.5）以后而不是之前的红系细胞中激活成人βmaj珠蛋白启动子，这一直是一个谜。我们在此发现，小鼠βmaj珠蛋白基因在E10.5胚胎的性腺-中肾区域和E14.5胎肝中的表达主要伴随着EKLF的核定位。相比之下，EKLF主要在E9.5血岛的红系细胞中的细胞质中，其中βmaj被沉默。值得注意的是，在培养的小鼠成人红白血病（MEL）细胞系中，二甲基亚砜（DMSO）或六亚甲基双乙酰胺（HMBA）诱导的βmaj珠蛋白基因的激活也被EKLF的亚细胞位置从细胞质转移到细胞核所抑制。在DMSO诱导的MEL细胞中，用核输出抑制剂阻断EKLF的核输入抑制了βmaj珠蛋白基因的转录。瞬时转染实验进一步表明，在DMSO诱导过程中，EKLF的全序列背景是MEL细胞中其亚细胞位置调节所必需的。最后，在E14.5胎肝细胞和诱导的MEL细胞中，β样珠蛋白基因座与PML癌基因结构域核小体共定位，并与EKLF、RNA聚合酶II和剪接因子SC 35一起浓缩。这些数据共同提供了第一个证据，即发育阶段和分化状态特异性调节EKLF的核转运可能是开启哺乳动物成体β珠蛋白基因转录所必需的步骤之一。
ABSTRACT Erythroid Krüppel-like factor (EKLF) is an essential transcription factor for mammalian β-like globin gene switching, and it specifically activates transcription of the adult β globin gene through binding of its zinc fingers to the promoter. It has been a puzzle that in the mouse, despite its expression throughout the erythroid development, EKLF activates the adult βmaj globin promoter only in erythroid cells beyond the stage of embryonic day 10.5 (E10.5) but not before. We show here that expression of the mouse βmaj globin gene in the aorta-gonad-mesonephros region of E10.5 embryos and in the E14.5 fetal liver is accompanied by predominantly nuclear localization of EKLF. In contrast, EKLF is mainly cytoplasmic in the erythroid cells of E9.5 blood islands in which βmaj is silenced. Remarkably, in a cultured mouse adult erythroleukemic (MEL) cell line, the activation of the βmaj globin gene by dimethyl sulfoxide (DMSO) or hexamethylene-bis-acetamide (HMBA) induction is also paralleled by a shift of the subcellular location of EKLF from the cytoplasm to the nucleus. Blockage of the nuclear import of EKLF in DMSO-induced MEL cells with a nuclear export inhibitor repressed the transcription of the βmaj globin gene. Transient transfection experiments further indicated that the full-sequence context of EKLF was required for the regulation of its subcellular locations in MEL cells during DMSO induction. Finally, in both the E14.5 fetal liver cells and induced MEL cells, the β-like globin locus is colocalized the PML oncogene domain nuclear body, and concentrated with EKLF, RNA polymerase II, and the splicing factor SC35. These data together provide the first evidence that developmental stage- and differentiation state-specific regulation of the nuclear transport of EKLF might be one of the steps necessary for the switch-on of the mammalian adult β globin gene transcription.
影响因子：
10.5
作者：
Sawado, T;Halow, J;Groudine, M
通讯作者：
Groudine, M
影响因子：
14.9
作者：
Dewang Zhou;Jin Ren;T. M. Ryan;N. Higgins;T. Townes
通讯作者：
Dewang Zhou;Jin Ren;T. M. Ryan;N. Higgins;T. Townes
DOI：
10.1073/pnas.0506164102
发表时间：
2005-11-22
影响因子：
11.1
作者：
Im, H;Grass, JA;Bresnick, EH
通讯作者：
Bresnick, EH