Zelko I, Sueyoshi T, Kawamoto T, Moore R, Negishi M
Pharmacogenetics Section, Laboratory of Reproductive and Developmental Toxicology, National Institute of Environmental Health Sciences, National Institutes of Health, Research Triangle Park, North Carolina 27709, USA.
Mol Cell Biol. 2001 Apr;21(8):2838-46. doi: 10.1128/MCB.21.8.2838-2846.2001.
In response to phenobarbital (PB) and other PB-type inducers, the nuclear receptor CAR translocates to the mouse liver nucleus (T. Kawamoto et al., Mol. Cell. Biol. 19:6318-6322, 1999). To define the translocation mechanism, fluorescent protein-tagged human CAR (hCAR) was expressed in the mouse livers using the in situ DNA injection and gene delivery systems. As in the wild-type hCAR, the truncated receptor lacking the C-terminal 10 residues (i.e., AF2 domain) translocated to the nucleus, indicating that the PB-inducible translocation is AF2 independent. Deletion of the 30 C-terminal residues abolished the receptor translocation, and subsequent site-directed mutagenesis delineated the PB-inducible translocation activity of the receptor to the peptide L313GLL316AEL319. Ala mutations of Leu313, Leu316, or Leu319 abrogated the translocation of CAR in the livers, while those of Leu312 or Leu315 did not affect the nuclear translocation. The leucine-rich peptide dictates the nuclear translocation of hCAR in response to various PB-type inducers and appears to be conserved in the mouse and rat receptors.
作为对苯巴比妥（PB）和其他PB类诱导剂的反应，核受体CAR转位至小鼠肝细胞核（T. Kawamoto等人，《分子与细胞生物学》19:6318 - 6322，1999年）。为了确定转位机制，使用原位DNA注射和基因递送系统在小鼠肝脏中表达了荧光蛋白标记的人CAR（hCAR）。与野生型hCAR一样，缺少C末端10个残基（即AF2结构域）的截短受体转位至细胞核，这表明PB诱导的转位不依赖于AF2。缺失30个C末端残基消除了受体转位，随后的定点诱变确定了受体对肽L313GLL316AEL319的PB诱导转位活性。Leu313、Leu316或Leu319的丙氨酸突变消除了CAR在肝脏中的转位，而Leu312或Leu315的突变则不影响核转位。富含亮氨酸的肽决定了hCAR对各种PB类诱导剂的核转位，并且在小鼠和大鼠受体中似乎是保守的。
