Identification and characterization of a novel 5 bp deletion in a putative insulin response element in the lipoprotein lipase gene.
Our aim was to identify an insulin response element (IRE) in the lipoprotein lipase (LPL) gene. We identified a 19 bp sequence as a putative IRE in LPL non-coding exon 10 using bioinformatics. Upon sequencing the IRE region, a novel 5 bp deletion was identified in Hispanics (N=406) with a carrier frequency of 4.2% but not in non-Hispanic whites (N=604) or Africans. Electrophoretic mobility shift assay revealed binding sites for regulatory factor(s) in muscle cell nuclear extracts with putative IRE sequence. Antibody supershift assay using human aorta smooth muscle cell nuclear extract revealed that Elk-1 specifically binds to putative IRE. TaqMan real-time RT-PCR of the 5 bp deletion, the mutant and wild type cDNA expressed in COS-1 and human muscle cells revealed that the 5 bp deletion was associated with modest reduction in LPL expression. There was also a slight reduction in LPL translation in the deletion mutant. Our data suggest the presence of an IRE in the 3'UTR of the LPL gene.
Yang
Li-Xia
LX
Department of Human Genetics, University of Pittsburgh, Pittsburgh, PA 15261, USA.
Razzaghi
Hamid
H
Hokanson
John E
JE
Kamboh
M Ilyas
MI
D000328:Adult; D000368:Aged; D000818:Animals; D020029:Base Pairing / Q000235:genetics*; D001483:Base Sequence; D019556:COS Cells; D002460:Cell Line; D002522:Chlorocebus aethiops; D004247:DNA / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D005091:Exons / Q000235:genetics; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D006801:Humans; D007328:Insulin / Q000494:pharmacology*; D008071:Lipoprotein Lipase / Q000235:genetics*; D008875:Middle Aged; D008969:Molecular Sequence Data; D018807:Polymorphism, Single-Stranded Conformational; D011485:Protein Binding / Q000187:drug effects; D020218:Response Elements / Q000235:genetics*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017384:Sequence Deletion; D055815:Young Adult; D050807:ets-Domain Protein Elk-1 / Q000378:metabolism
D007328:Insulin; D050807:ets-Domain Protein Elk-1; D004247:DNA; D008071:Lipoprotein Lipase