Jeung E B, Fan N C, Leung P C, Herr J C, Freemerman A, Krisinger J
Department of Obstetrics and Gynecology, University of British Columbia, Vancouver, Canada.
Mol Reprod Dev. 1995 Apr;40(4):400-7. doi: 10.1002/mrd.1080400403.
Expression of the Calbindin-D9k (CaBP-9k) gene was studied in the baboon. Northern blot analysis using a human CaBP-9k cDNA probe detected expression in duodenum but not in uterus and placenta. Reverse transcription/polymerase chain reaction (RT/PCR) confirmed this expression pattern and indicated a high degree of identity between the baboon and human CaBP-9k mRNAs. PCR was employed to amplify the intron A region of the baboon CaBP-9k gene using human-derived primers and baboon genomic DNA. The baboon intron was closely related to the human CaBP-9k intron A, including the presence a complete Alu-repetitive element. Most significantly, a 13 nucleotide long element at the 5' end of the baboon intron matched exactly the human sequence. This element represents a nonfunctional variation of an estrogen response element found at the same location in the rat CaBP-9k gene. The rat element functions as an enhancer and mediates uterine and possibly placental CaBP-9k expression in the rat and probably most other mammals. The finding of a modified ERE in baboon as in human suggests that during primate evolution the expression of this mammalian-specific gene has been eliminated in uterus and placenta. This scenario raises the question of the role of CaBP-9k in these reproductive tissues.
在狒狒中研究了钙结合蛋白-D9k（CaBP-9k）基因的表达。使用人CaBP-9k cDNA探针进行的Northern印迹分析检测到十二指肠中有表达，但子宫和胎盘中没有。逆转录/聚合酶链反应（RT/PCR）证实了这种表达模式，并表明狒狒和人CaBP-9k mRNA之间具有高度的同一性。使用人源引物和狒狒基因组DNA，通过PCR扩增狒狒CaBP-9k基因的内含子A区域。狒狒内含子与人CaBP-9k内含子A密切相关，包括存在一个完整的Alu重复元件。最显著的是，狒狒内含子5'端一个13个核苷酸长的元件与人类序列完全匹配。该元件代表在大鼠CaBP-9k基因相同位置发现的雌激素反应元件的无功能变体。大鼠元件起增强子作用，介导大鼠以及可能大多数其他哺乳动物子宫和胎盘CaBP-9k的表达。在狒狒中与人一样发现了修饰的雌激素反应元件，这表明在灵长类动物进化过程中，这种哺乳动物特异性基因在子宫和胎盘中的表达已被消除。这种情况引发了CaBP-9k在这些生殖组织中作用的问题。
