9 research outputs found
Common variants in signal peptide sequences; modelling effects and relationship to function
peer reviewe
The effects of a single nucleotide polymorphism in SLCO1B1 on the pharmacodynamics of pravastatin
AI
Variation in USF1 shows haplotype effects, gene : gene and gene : environment associations with glucose and lipid parameters in the European Atherosclerosis Research Study II
The distribution of isoelectric points of human soluble proteins and in particular of the enzyme products of 88 human gene loci
Determination Of The Functionality Of Common Apoa5 Polymorphisms
Common variants of APOA5 have consistently shown association with differences in
plasma triglyceride (TG) levels. These single nucleotide polymorphisms (SNPs)
fall into three common haplotypes: APOA5*1, with common alleles at all sites;
APOA5*2, with rare alleles of -1131T--> C, -3A--> G, 751G--> T, and 1891T--> C;
and APOA5*3, distinguished by the c56C--> G (S19W). Molecular modeling of the
apoAV signal peptide (SP) showed an increased angle of insertion (65 degrees ) at
the lipid/water interface of Trp-19 SP compared with Ser-19 SP (40 degrees ),
predicting reduced translocation. This was confirmed by 50% reduction of
Trp-19-encoded SP.secretory alkaline phosphatase (SEAP) fusion protein secreted
into the medium from HepG2 cells compared with the Ser-19.SEAP fusion protein (p
< 0.002). Considering APOA5*2 SNPs, there was no significant difference in the
relative luciferase expression in Huh7 cells transiently transfected with a
-1131T construct compared with the -1131C (fragments -1177 to -516 or -1177 to
-3). Similarly, for the -3A--> G in the Kozak sequence, in vitro
transcription/translation assays and primer extension inhibition assays showed no
alternate AUG initiation codon usage, demonstrating that -3A--> G did not
influence translation efficiency. Although 1891T--> C in the 3'-untranslated
region disrupts a putative Oct-1 transcription factor binding site, when inserted
3' of the luciferase gene the T--> C change demonstrated no significant
difference in luciferase expression. Thus, association of APOA5*2 SNPs with TG
levels is not due to the individual effects of any of these SNPs, although
cooperativity between the SNPs cannot be excluded. Alternatively, the effect on
TG levels may reflect the strong linkage disequilibrium with the functional APOC3
SNPs
Novel and recurrent LDLR gene mutations in Pakistani hypercholesterolemia patients
Item does not contain fulltextThe majority of patients with the autosomal dominant disorder familial hypercholesterolemia (FH) carry novel mutations in the low density lipoprotein receptor (LDLR) that is involved in cholesterol regulation. In different populations the spectrum of mutations identified is quite different and to date there have been only a few reports of the spectrum of mutations in FH patients from Pakistan. In order to identify the causative LDLR variants the gene was sequenced in a Pakistani FH family, while high resolution melting analysis followed by sequencing was performed in a panel of 27 unrelated sporadic hypercholesterolemia patients. In the family a novel missense variant (c.1916T > G, p.(V639G)) in exon 13 of LDLR was identified in the proband. The segregation of the identified nucleotide change in the family and carrier status screening in a group of 100 healthy subjects was done using restriction fragment length polymorphism analysis. All affected members of the FH family carried the variant and none of the non-affected members nor any of the healthy subjects. In one of the sporadic cases, two sequence changes were detected in exon 9, one of these was a recurrent missense variant (c.1211C > T; p.T404I), while the other was a novel substitution mutation (c.1214 A > C; N405T). In order to define the allelic status of this double heterozygous individual, PCR amplified fragments were cloned and sequenced, which identified that both changes occurred on the same allele. In silico tools (PolyPhen and SIFT) were used to predict the effect of the variants on the protein structure, which predicted both of these variants to have deleterious effect. These findings support the view that there will be a novel spectrum of mutations causing FH in patients with hypercholesterolaemia from Pakistan