Negative and positive effects of an IAP-LTR on nearby Pcdaalpha gene expression in the central nervous system and neuroblastoma cell lines.
Intracisternal A-particles (IAPs) are defective retrovirions encoded by members of a large family of endogenous proviral elements in the murine genome. An intact IAP element was found in the protocadherin alpha (Pcdhalpha) gene cluster of five laboratory mouse strains. However, IAP insertion was not detected in three wild mouse strains we investigated. This IAP insertion caused the disruption of one variable exon of laboratory mouse and down-regulated expression of the Pcdhalpha v8 exon, which is located just downstream of the IAP in the brain following the methylation of 5' regulatory region of Pcdhalpha v8. In contrast, the Pcdhalpha v8 exon was highly expressed in mouse neuroblastoma cell lines. This suggested that the IAP insertion activates the expression of the nearby Pcdhalpha v8 exon in these cell lines. In fact, the Pcdhalpha v8 exon expression was driven by the IAP-long terminal repeat (LTR) following the de-methylation of 5' regulatory region of Pcdhalpha v8. To investigate the promoter activity of the IAP, we constructed an IAP-LTR-ECFP reporter gene and introduced it into neuroblastoma, melanoma, lymphoma, and plasmacytoma cell lines. Interestingly, ECFP-positive cells were observed only in the neuroblastoma cell lines. Moreover, there were no differences in the promoter activities of the IAP-LTR whether it was in the sense or complimentary orientation. Thus, this IAP-LTR has negative and positive regulation on near by gene expression in the brain and neuroblastoma cell lines.
KOKORO Biology Group, Laboratories for Integrated Biology, Graduate School of Frontier Biosciences, Osaka University, Yamadaoka 1-3, Suita 565-0871, Japan. sugino@fbs.osaka-u.ac.jp
Hidehiko
H
Sugino
Tomoko
T
Toyama
Yusuke
Y
Taguchi
Shigeyuki
S
Esumi
Mitsuhiro
M
Miyazaki
Takeshi
T
Yagi
D000818:Animals; D001483:Base Sequence; D015820:Cadherins / Q000235:genetics*; D045744:Cell Line, Tumor; D002490:Central Nervous System / Q000378:metabolism*; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D005796:Genes / Q000235:genetics; D007426:Genes, Intracisternal A-Particle / Q000235:genetics*; D049452:Green Fluorescent Proteins; D008164:Luminescent Proteins / Q000235:genetics / Q000378:metabolism; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D008815:Mice, Inbred Strains; D008856:Microscopy, Fluorescence; D008969:Molecular Sequence Data; D016254:Mutagenesis, Insertional; D009447:Neuroblastoma / Q000235:genetics / Q000473:pathology; D011401:Promoter Regions, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D018626:Retroelements / Q000235:genetics; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012689:Sequence Homology, Nucleic Acid; D013045:Species Specificity; D020079:Terminal Repeat Sequences / Q000235:genetics*; D013997:Time Factors; D014162:Transfection
D015820:Cadherins; D008164:Luminescent Proteins; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D018626:Retroelements; D049452:Green Fluorescent Proteins