Nagata T, Weiss E H, Abe K, Kitagawa K, Ando A, Yara-Kikuti Y, Seldin M F, Ozato K, Inoko H, Taketo M
Banyu Tsukuba Research Institute (Merck), Japan.
Immunogenetics. 1995;41(2-3):83-90. doi: 10.1007/BF00182317.
Retinoid X receptors (RXRs) are zinc finger-containing nuclear transcription factors. They belong to the nuclear receptor superfamily that contains retinoid receptors, vitamin D receptors, thyroid hormone receptors, and steroid hormone receptors as well as the so-called orphan receptors. We previously mapped all three RXR genes on mouse chromosomes, using a panel of Mus spretus-Mus musculus interspecific backcross mice: Namely, the RXRA-gene (Rxra) on Chr 2 near the centromere, the RXRB gene (Rxrb) on Chr 17 in the H2 region, and the RXRG gene (Rxrg) on distal Chr 1. Using cosmid clones that cover the major histocompatibility complex (MHC) region, we determined the precise physical map positions of the gene encoding mouse and human RXRB, respectively. The mouse gene (Rxrb) maps between H2-Ke4 and H2-Ke5: namely, immediately telomeric to H2-Ke4 which encodes a histidine-rich transmembrane protein, and 12 kilobases centromeric to H2-Ke5 which is expressed in lymphoid tissues. Rxrb and H2-Ke4 are transcribed into opposite directions from a CpG-rich promoter of about 250 base pairs. This gene organization is well conserved also in the human genome at the HLA-DP subregion of Chr 6p, underscoring the strong conservation of the gene organization in the MHC region between the two mammals.
视黄酸X受体（RXRs）是含锌指结构的核转录因子。它们属于核受体超家族，该家族包含视黄酸受体、维生素D受体、甲状腺激素受体、类固醇激素受体以及所谓的孤儿受体。我们先前利用一组小家鼠-家鼠种间回交小鼠，将所有三个RXR基因定位到了小鼠染色体上：即，位于2号染色体着丝粒附近的RXRA基因（Rxra），位于17号染色体H2区域的RXRB基因（Rxrb），以及位于1号染色体远端的RXRG基因（Rxrg）。利用覆盖主要组织相容性复合体（MHC）区域的黏粒克隆，我们分别确定了编码小鼠和人类RXRB的基因的精确物理图谱位置。小鼠基因（Rxrb）定位于H2-Ke4和H2-Ke5之间：即，紧邻编码富含组氨酸的跨膜蛋白的H2-Ke4的端粒侧，且位于在淋巴组织中表达的H2-Ke5的着丝粒侧12千碱基处。Rxrb和H2-Ke4从一个约250个碱基对的富含CpG的启动子以相反方向转录。在人类基因组6号染色体p臂的HLA-DP亚区域，这种基因组织也得到了很好的保守，这突出了这两种哺乳动物MHC区域中基因组织的高度保守性。
