Runkel Fabian, Michels Marion, Franz Thomas
Anatomisches Institut, University of Bonn, Nussallee 10, D-53115 Bonn, Germany.
Mamm Genome. 2003 Oct;14(10):665-72. doi: 10.1007/s00335-003-2282-z.
We have investigated the expression of Fxyd3 and Lgi4 in the adult mouse by Northern blot analyses and in situ hybridization. Murine Fxyd3 and Lgi4 have been mapped to the same locus on mouse Chromosome (Chr) 7, where the last exon of Fxyd3 completely overlaps with the 3'UTR in the last exon of Lgi4, which is transcribed in the opposite orientation. The Fxyd3 gene (formerly called Mat-8) encodes an 8-kDa transmembrane protein that is upregulated in mammary tumors and can induce a chloride conductance upon RNA injection into Xenopus oocytes. Fxyd3 is a member of the Fxyd family of which several members are tissue-specific regulators of ion channels. Murine Lgi4 is a recently described member of the leucine-rich-repeat gene family Lgi. Northern blot analyses demonstrated a 0.6-kb Fxyd3 transcript with abundant expression in the murine skin, colon, and mammary gland, but low level expression in the brain. In contrast, a 3.2-kb Lgi4 transcript was abundant in brain, with lower level expression in colon. Lgi4 transcription in the skin was detectable only by RT-PCR. A Fxyd3-specific sense cRNA probe hybridized to a transcript in Northern blots of brain and colon RNA that co-migrated with the Lgi4 mRNA. In situ hybridization experiments revealed that both Fxyd3 and Lgi4 were expressed in the same tissue compartments in skin, uterus, intestine, mammary gland, and brain. These results demonstrate that Fxyd3 and Lgi4 transcripts potentially form double-stranded RNA molecules in many cell types in vivo, which may impact on their respective expression.
我们通过Northern印迹分析和原位杂交研究了成年小鼠中Fxyd3和Lgi4的表达。小鼠Fxyd3和Lgi4已被定位到小鼠染色体（Chr）7上的同一基因座，其中Fxyd3的最后一个外显子与Lgi4最后一个外显子中的3'UTR完全重叠，且二者转录方向相反。Fxyd3基因（以前称为Mat-8）编码一种8 kDa的跨膜蛋白，该蛋白在乳腺肿瘤中上调，并且在将RNA注射到非洲爪蟾卵母细胞中时可诱导氯化物电导。Fxyd3是Fxyd家族的成员之一，该家族的几个成员是离子通道的组织特异性调节因子。小鼠Lgi4是富含亮氨酸重复基因家族Lgi中最近描述的成员。Northern印迹分析显示，有一个0.6 kb的Fxyd3转录本在小鼠皮肤、结肠和乳腺中大量表达，但在脑中表达水平较低。相比之下，一个3.2 kb的Lgi4转录本在脑中大量存在，在结肠中的表达水平较低。仅通过RT-PCR可检测到皮肤中的Lgi4转录。一种Fxyd3特异性正义cRNA探针与脑和结肠RNA的Northern印迹中的一个转录本杂交，该转录本与Lgi4 mRNA共迁移。原位杂交实验表明，Fxyd3和Lgi4在皮肤、子宫、肠道、乳腺和脑中的相同组织区室中表达。这些结果表明，Fxyd3和Lgi4转录本在体内许多细胞类型中可能形成双链RNA分子，这可能会影响它们各自的表达。
