PQBP-1 is expressed predominantly in the central nervous system during development.
Mutations of PQBP-1 (polyglutamine binding protein-1) have been shown recently to cause human mental retardation accompanied by microcephaly at a high frequency. As a first step towards understanding the molecular basis of this developmental anomaly, we analysed developmental expression of PQBP-1 by in situ hybridization, immunohistochemistry and Western blot analysis. Although it had been shown by Northern blot analysis that PQBP-1 mRNA is expressed in multiple organs in adult mice, our present results revealed that PQBP-1 mRNA and protein are dominantly expressed in the central nervous system (CNS) in embryos and in newborn mice. The mean expression level of PQBP-1 reaches a peak around birth and is down-regulated in adulthood. Furthermore, the expression pattern in the CNS changes remarkably following birth. PQBP-1 mRNA in the cerebral cortex is high in embryos but it rapidly decreases after birth. PQBP-1 mRNA increases in external and internal granular cell layers of the cerebellum from postnatal day 1 (P1) to P5. In addition, expression in the subventricular zone, where neurogenesis occurs, was high from P5 to adulthood. Collectively, these findings suggest that PQBP-1 might be involved in neuronal proliferation and/or maturation. These ideas may be relevant to the insufficient growth of brain structure reported in PQBP-1-linked human mental retardation.
Qi
Yunglong
Y
Department of Neuropathology, Medical Research Institute, Tokyo Medical and Dental University, 21st Century COE, Brain Integration and Its Disorders, 1-5-45, Yushima, Bunkyo-ku, Tokyo 113-8510, Japan.
Hoshino
Masataka
M
Wada
Yo-ichi
Y
Marubuchi
Shigeki
S
Yoshimura
Natsue
N
Kanazawa
Ichiro
I
Shinomiya
Ken-ichi
K
Okazawa
Hitoshi
H
D000818:Animals; D000831:Animals, Newborn / Q000502:physiology; D015153:Blotting, Western; D001921:Brain / Q000254:growth & development; D001923:Brain Chemistry / Q000235:genetics; D002352:Carrier Proteins / Q000096:biosynthesis / Q000235:genetics*; D002490:Central Nervous System / Q000254:growth & development* / Q000378:metabolism*; D002540:Cerebral Cortex / Q000378:metabolism; D004268:DNA-Binding Proteins; D004622:Embryo, Mammalian / Q000378:metabolism; D005260:Female; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000378:metabolism; D007150:Immunohistochemistry; D017403:In Situ Hybridization; D051379:Mice; D008810:Mice, Inbred C57BL; D009687:Nuclear Proteins / Q000096:biosynthesis / Q000235:genetics*; D016376:Oligonucleotides, Antisense / Q000378:metabolism; D011247:Pregnancy; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics
D002352:Carrier Proteins; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D016376:Oligonucleotides, Antisense; C492272:Pqbp1 protein, mouse; D012333:RNA, Messenger; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases