The baboon expresses the calbindin-D9k gene in intestine but not in uterus and placenta: implication for conservation of the gene in primates.
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.
Jeung
E B
EB
Department of Obstetrics and Gynecology, University of British Columbia, Vancouver, Canada.
Fan
N C
NC
Leung
P C
PC
Herr
J C
JC
Freemerman
A
A
Krisinger
J
J
D000818:Animals; D001483:Base Sequence; D064026:Calbindins; D017124:Conserved Sequence; D005260:Female; D015870:Gene Expression; D006801:Humans; D007413:Intestinal Mucosa / Q000378:metabolism*; D008969:Molecular Sequence Data; D009928:Organ Specificity; D010215:Papio; D010920:Placenta / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D011247:Pregnancy; D012333:RNA, Messenger / Q000032:analysis; D064030:S100 Calcium Binding Protein G / Q000032:analysis* / Q000235:genetics; D014599:Uterus / Q000378:metabolism*
D064026:Calbindins; D012333:RNA, Messenger; D064030:S100 Calcium Binding Protein G; C576506:S100G protein, human; C576508:S100g protein, rat