title: Functional pseudogenes inhibit the superoxide production.
abstract: We recently discovered a dynamic copy number variation on the NCF1 (neutrophil cytosolic factor 1) pseudogenes in human populations. In this study, we investigated whether these pseudogenes are functional or junk as described before. We sequenced the RNAs transcribed from the genome of this locus, and discovered over 10 splicing isoforms from the NCF1 pseudogenes. We cloned 4 splicing isoforms into expression vectors and introduced them into human vascular endothelial cells by transient transfection. We then used two chemical approaches to measure the superoxide production in the cells with and without these pseudogene overexpression. Our data showed that three pseudogene splicing products remarkably reduced the superoxide production after the GFP (Green fluorescent protein) normalization. We used an anti-HA (Hemagglutinin A) tag antibody to stain the cells and confirmed that the proteins transcribed from the NCF1 pseudogene were exclusively localized in the cytoplasm in the perinuclear area in the transient transfection assays. We further examined the tissue distribution of these splicing isoforms of NCF1 pseudogenes in human tissues by quantitative real-time PCR analysis. Our data showed that although these splicing variants are ubiquitously expressed in non-immune tissues in human, they seem to be under a tight control of transcription regulation and show a non-random distribution pattern across tissues. This study challenges the concept that pseudogenes in human genome are only junks without biological functions. Moreover, it suggests that those pseudogenes in human genome may serve as a natural resource for novel drug discovery.
authors.affiliation: Department of Cardiovascular Medicine, Key Laboratory of Molecular Cardiology, Cardiovascular Research Center, and Key Laboratory of Environment and Genes Related to Diseases, First Affiliated Hospital of Medical School, Xi'an Jiaotong University, Xi'an, 710061, Shaanxi, China ; Cardiovascular Research Institute, Morehouse School of Medicine, Atlanta, Georgia 30310, USA.
authors.forename: Wei
authors.initials: W
authors.lastname: Xu
authors.affiliation: Cardiovascular Research Institute, Morehouse School of Medicine, Atlanta, Georgia 30310, USA ; 4DGENOME Inc, Atlanta,Georgia 30092, GA.
authors.forename: Li
authors.initials: L
authors.lastname: Ma
authors.affiliation: Cardiovascular Research Institute, Morehouse School of Medicine, Atlanta, Georgia 30310, USA.
authors.forename: Wenzhi
authors.initials: W
authors.lastname: Li
authors.affiliation: Cardiovascular Research Institute, Morehouse School of Medicine, Atlanta, Georgia 30310, USA.
authors.forename: Tiffany A
authors.initials: TA
authors.lastname: Brunson
authors.affiliation: Cardiovascular Research Institute, Morehouse School of Medicine, Atlanta, Georgia 30310, USA.
authors.forename: Xiaohua
authors.initials: X
authors.lastname: Tian
authors.affiliation: Cardiovascular Research Institute, Morehouse School of Medicine, Atlanta, Georgia 30310, USA.
authors.forename: Jendai
authors.initials: J
authors.lastname: Richards
authors.affiliation: Cardiovascular Research Institute, Morehouse School of Medicine, Atlanta, Georgia 30310, USA ; Department of Obstetrics and Gynecology, First Affiliated Hospital, Xi'an Jiaotong University, Xi'an, 710061, Shaanxi, China.
authors.forename: Qiling
authors.initials: Q
authors.lastname: Li
authors.affiliation: Cardiovascular Research Institute, Morehouse School of Medicine, Atlanta, Georgia 30310, USA.
authors.forename: Tameka
authors.initials: T
authors.lastname: Bythwood
authors.affiliation: Department of Cardiovascular Medicine, Key Laboratory of Molecular Cardiology, Cardiovascular Research Center, and Key Laboratory of Environment and Genes Related to Diseases, First Affiliated Hospital of Medical School, Xi'an Jiaotong University, Xi'an, 710061, Shaanxi, China.
authors.forename: Zuyi
authors.initials: Z
authors.lastname: Yuan
authors.affiliation: Department of Cardiovascular Medicine, Key Laboratory of Molecular Cardiology, Cardiovascular Research Center, and Key Laboratory of Environment and Genes Related to Diseases, First Affiliated Hospital of Medical School, Xi'an Jiaotong University, Xi'an, 710061, Shaanxi, China ; Cardiovascular Research Institute, Morehouse School of Medicine, Atlanta, Georgia 30310, USA ; Department of Medicine, Morehouse School of Medicine, Atlanta, Georgia 30310, USA ; Department of Obstetrics and Gynecology, First Affiliated Hospital, Xi'an Jiaotong University, Xi'an, 710061, Shaanxi, China ; 4DGENOME Inc, Atlanta,Georgia 30092, GA.
authors.forename: Qing
authors.initials: Q
authors.lastname: Song
keywords: pseudogene