title: Effect ofAPOL1disease risk variants onAPOL1gene product.
abstract: Gene sequence mutations may alter mRNA transcription, transcript stability, protein translation, protein stability and protein folding. Apolipoprotein L1 (APOL1) has two sets of sequence variants that are risk factors for kidney disease development, APOL1G1 (substitution mutation) and APOL1G2 (deletion mutation). Our present study focuses on the impact of these variants onAPOL1mRNA transcription and translation. APOL1 plasmids (EV, G0, G1 and G2) were transfected into human embryonic kidney (HEK) 293T cells. APOL1 variant expression was observed to be significantly lower than that of APOL1G0. Podocyte cell lines stably expressing APOL1 transgenes also showed lower levels of APOL1 expression of APOL1 variants (G1 and G2) compared with APOL1G0 by Western blotting and FACS analysis. The enhanced expression of GRP78 by podocytes expressing APOL1 variants would indicate endoplasmic reticulum (ER) stress. Bioinformatics evaluation using two different programs (MUPro and I-Mutant 2.0) predicted that APOL1 variants were less stable than APOL1G0. Concomitant with protein levels,APOL1mRNA levels were also depressed following induction of APOL1 variant compared with APOL1G0 in both proliferating and differentiated podocytes.APOL1mRNA transcript stability was tested after actinomycin D pulsing;APOL1G1andAPOL1G2mRNAs transcript decayed 10-15% and 15-20% (within a period of 0.5-3 h) respectively. Our data suggest that down-regulated APOL1 protein expression in APOL1 variants is due to compromised transcription and decay of the APOL1 variant transcripts.
authors.affiliation: Renal Molecular Research Laboratory, Feinstein Institute for Medical Research, Hofstra North Shore LIJ Medical School, New York, U.S.A.
authors.forename: Shabirul
authors.initials: S
authors.lastname: Haque
authors.affiliation: Renal Molecular Research Laboratory, Feinstein Institute for Medical Research, Hofstra North Shore LIJ Medical School, New York, U.S.A.
authors.forename: Gauri
authors.initials: G
authors.lastname: Patil
authors.affiliation: Renal Molecular Research Laboratory, Feinstein Institute for Medical Research, Hofstra North Shore LIJ Medical School, New York, U.S.A.
authors.forename: Abheepsa
authors.initials: A
authors.lastname: Mishra
authors.affiliation: Renal Molecular Research Laboratory, Feinstein Institute for Medical Research, Hofstra North Shore LIJ Medical School, New York, U.S.A.
authors.forename: Xiqian
authors.initials: X
authors.lastname: Lan
authors.affiliation: Center for Health Disparity Reseaerch, Meharry Medical College, Nashville, TN, U.S.A.
authors.forename: Waldemar
authors.initials: W
authors.lastname: Popik
authors.affiliation: Renal Molecular Research Laboratory, Feinstein Institute for Medical Research, Hofstra North Shore LIJ Medical School, New York, U.S.A.
authors.forename: Ashwani
authors.initials: A
authors.lastname: Malhotra
authors.affiliation: Nephrology and Molecular Medicine, Technion, Institute of Technology and Rambam Medical Center, Haifa, Israel.
authors.forename: Karl
authors.initials: K
authors.lastname: Skorecki
authors.affiliation: Renal Molecular Research Laboratory, Feinstein Institute for Medical Research, Hofstra North Shore LIJ Medical School, New York, U.S.A. psinghal@nshs.edu.
authors.forename: Pravin C
authors.initials: PC
authors.lastname: Singhal
mesh_terms: D019943:Amino Acid Substitution; D000075944:Apolipoprotein L1 / Q000235:genetics*; D002454:Cell Differentiation; D002460:Cell Line; D049109:Cell Proliferation; D000091342:Endoplasmic Reticulum Chaperone BiP; D017353:Gene Deletion; D005786:Gene Expression Regulation; D014644:Genetic Variation; D057809:HEK293 Cells; D006360:Heat-Shock Proteins / Q000235:genetics; D006801:Humans; D007674:Kidney Diseases / Q000235:genetics*; D050199:Podocytes / Q000166:cytology / Q000378:metabolism; D014176:Protein Biosynthesis; D012333:RNA, Messenger / Q000235:genetics; D014158:Transcription, Genetic
chemical_list: C108666:APOL1 protein, human; D000075944:Apolipoprotein L1; D000091342:Endoplasmic Reticulum Chaperone BiP; C000717247:HSPA5 protein, human; D006360:Heat-Shock Proteins; D012333:RNA, Messenger
keywords: APOL1; APOL1 disease risk variants; APOL1 gene product