The functional interaction on in vitro gene expression of APOA5 SNPs, defining haplotype APOA5*2, and their paradoxical association with plasma triglyceride but not plasma apoAV levels

被引：35

作者：

Palmen, Jutta ^{[1
]}

Smith, Andrew J. P. ^{[1
]}

Dorfmeister, Birgit ^{[1
]}

Putt, Wendy ^{[1
]}

Humphries, Steve E. ^{[1
]}

Talmud, Philippa J. ^{[1
]}

机构：

[1] UCL, Dept Med, Div Cardiovasc Genet, London WC1E 6JF, England

来源：

BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR BASIS OF DISEASE | 2008年 / 1782卷 / 7-8期

关键词：

APOA5*2; plasma apoAV; -1131T > C; -3A > G; +1891T > C; Kozak sequence; plasma TG;

D O I：

10.1016/j.bbadis.2008.03.003

中图分类号：

Q5 [生物化学]; Q7 [分子生物学];

学科分类号：

071010 ; 081704 ;

摘要：

Plasma triglycericle (TG) and apoAV levels are reported to be positively correlated, yet SNPs defining haplotype APOA5*2 have consistently shown association with elevated plasma triglycericle (TG) but not plasma apoAV levels. We previously reported that individually -1131T > C, -3A > G and + 1891T > C did not influence luciferase activity or in vitro translation efficiency. To investigate the combined effect of these SNPs additional constructs were examined. Compared to the wildtype -1131 T/-3A/+1891T (TAT), the triple rare allele construct -1131 (C) under bar/-3 (G) under bar/+1891 (C) under bar ((CGC) under bar) conferred 46% lower luciferase activity (p < 0.0001), showing these SNPs are acting cooperatively. Although only these two combinations occur in vivo, we experimentally altered the TAT construct one site at a time; -3G (T (G) under barT) had the largest effect (94% lower luciferase), with lesser effects from CAT (-77%) and TA (C) under bar (-70.3%) (all p < 0.0001). Deletion constructs excluding one site at a time showed that -3 (G) under bar /1891 (C) under bar (-(GC) under bar) in combination, compared to -AT, was having the largest effect on luciferase activity (-59%, p=0.055). Using sequence homology and EMSA analysis no transcription factor binding at -1131 or +1891 was identified, though +1891 lies within a putative mRNA stability motif Taken together, these data identify -3A > G in the Kozak sequence as functional, affecting translation initiation and driving the haplotype effects, while showing interaction with +1891T > C and to a lesser extent -1131T > C. A paradox arises since these results predict that APOA5*2 will lead to reduced apoAV with concomitant reduced LPL activation or lipoprotein-receptor interaction, resulting in higher plasma TG levels. We conclude that APOA5 expression, and not circulating plasma apoAV levels, is causatively associated with plasma TG levels. (C) 2008 Elsevier B.V. All rights reserved.

引用

页码：447 / 452

页数：6