PubMed Health⌕ Search
Home/Archive/PubMed

PubMed · 1418920

Molecular basis for apo A-IV polymorphisms.

H Tenkanen·C Ehnholm
View original source ↗Export metadata ↓

Abstract

Apolipoprotein (apo) A-IV is involved in the metabolism of triglyceride-rich lipoproteins and high-density lipoproteins and may thus play an important role in lipid metabolism, although the precise physiological function of apo A-IV is unknown. Structural and functional alterations of apolipoproteins, caused by a variety of mutations, have been shown to influence lipoprotein metabolism in several ways. Genetic studies are consistent with a single locus for apo A-IV with two main codominant alleles A-IV1 and A-IV2. The basis behind some of these electrophoretic variants has been determined on a molecular level by the aid of the polymerase chain reaction and sequencing of the amplified DNA. For instance, apo A-IV1 and apo A-IV2 alleles are explained by glutamine for histidine change of amino acid 360. Furthermore, several polymorphisms not leading to charge differences have been characterized. The genetic variability of apo A-IV may be of help in elucidating the functional role of apo A-IV in lipoprotein metabolism. In our study, the frequencies of the alleles due to Gln360-->His and Thr347-->Ser substitutions in a Finnish population sample were similar to those reported from other populations. In addition we have identified a novel genetic polymorphism of apo A-IV, Asn127-->Ser. In the Finnish population the asparagine for serine change of amino acid 127 was the most common apo A-IV polymorphism. There are no reports from other populations concerning this polymorphism.(ABSTRACT TRUNCATED AT 250 WORDS)

Explore related subjects

AllelesApolipoproteins ACoronary DiseaseElectrophoresisFemaleGenesGenetic VariationGenotypeHumansHyperlipidemiasLipidsLipoproteinsMalePolymorphism, GeneticComparative StudyJournal Article

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

H Tenkanen, C Ehnholm. 1992. Molecular basis for apo A-IV polymorphisms.. https://doi.org/10.3109/07853899209147839

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed2026

A de novo algorithm for allele reconstruction from Oxford nanopore amplicon reads, with application to CYP2D6.

MOTIVATION: The Oxford Nanopore Technologies' sequencing platform offers a path towards bedside genomics, producing long reads that can completely cover a gene of interest, and detect any known or novel variant the gene contains. However, the analysis of these long reads to identify actionable genotypes remains challenging and typically requires customization depending on the target gene. RESULTS: Here, we describe a generic algorithm to accurately reconstruct allele sequences derived from long-reads of amplicon-based data. Rather than calling variants directly from these long-reads, our method takes a "sequence-first" approach, performing an unbiased reconstruction of the underlying amplicon sequences to generate high-confidence reconstructed allele sequences. This is done without user input of the target gene, allowing for any source amplicon to be reconstructed. These high-confidence reconstructed allele sequences are then compared to the genomic reference sequence of the gene to infer the specific diplotype present in the sample. This approach is agnostic towards the number of genes and alleles present and readily detects novel variants. We demonstrate our approach using three independent data sets for CYP2D6, a diverse and complex gene with over 175 known alleles of clinical significance. We show how our approach can accurately recover validated CYP2D6 diplotypes from 20 Coriell samples covering 14 distinct alleles, using different amplicons, flow cell versions, and depths. This includes inferring occurrences of allele duplication events from relative abundances of each allele, a critical factor for ascribing functional effects to a diplotype. Further, we demonstrate our approach's utility for other genomic regions, including HLA. AVAILABILITY: Custom code is available at the following GitHub repository, along with instructions for use and test data: https://github.com/scottdbrown/allele-reconstruction-long-read-amplicon-data. A snapshot of the code at the time of publication is available on Zenodo.org; doi 10.5281/zenodo.19716004. Raw .fastq sequence data for our three sequencing runs is available at the SRA under Bioproject PRJNA1357883 (https://www.ncbi.nlm.nih.gov/bioproject/1357883).

Alleles↗
PubMed2026

Supergene control of chiral development in mirror-image flowers.

How genes determine the development of chiral structures is a fascinating question. The reciprocal placement of female and male organs on opposite sides of mirror-image flowers promotes efficient cross-pollination. Here, we identified that in butterfly lilies, female and male organs deflect by a combination of genetically controlled chirality and gravitropism, orienting left and right with respect to an external rather than internal reference axis. We found coordinated organ placement to be controlled by a hemizygous supergene containing two candidate causal loci, MIR156-R and YUCCA-R, that are responsible for opposite female and male organ orientation, respectively. The resulting differential placement of pollen carrying the two supergene alleles on pollinators' bodies leads to their transfer to the stigmas of flowers with opposite handedness and maintenance of the reproductive polymorphism.

Alleles↗
PubMed2026

DirectASRM: uncovering allele-specific post-transcriptional RNA modifications through direct RNA sequencing.

SUMMARY: We developed DirectASRM, a comprehensive database for the systematic identification, integration, and annotation of allele-specific RNA modifications (ASRMs) from direct RNA sequencing data. DirectASRM enables single-base, transcript-level detection of ASRMs across multiple RNA modification types, diverse organisms and condition-specific contexts. The database further evaluates the confidence of each ASRM-SNP pair association within isoform context by jointly considering statistical evidence of allelic modification imbalance and independent support from external next-generation sequencing (NGS) - based RNA modification resources. DirectASRM also provides extensive functional annotations for ASRMs and their associated variants, including intra-sample transcript-level allele-specific expression (ASE) and allele-specific splicing, as well as additional post-transcriptional regulatory features such as miRNA binding, circRNA, RNA-protein interactions, and disease relevance. Overall, DirectASRM serves as a comprehensive resource that supports systematic investigation of the potential functional impact of genetic variants in epitranscriptomic regulation. AVAILABILITY AND IMPLEMENTATION: DirectASRM database is freely accessible at http://modinfor.com/DirectASRM/. DirectASRM pipeline is available at GitHub (https://github.com/jiayin1101/DirectASRM_pipeline) and Zenodo (DOI: https://doi.org/10.5281/zenodo.19876077).

Alleles↗