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Biomedical subjects

D S Fredrickson

Publications and source records attributed to D S Fredrickson.

At least 19 recordsLinked to original sources
PubMed2000

Complete genomic sequence of the human ABCA1 gene: analysis of the human and mouse ATP-binding cassette A promoter.

The ABCA1 gene, a member of the ATP-binding cassette A (ABCA1) transporter superfamily, encodes a membrane protein that facilitates the cellular efflux of cholesterol and phospholipids. Mutations in ABCA1 lead to familial high density lipoprotein deficiency and Tangier disease. We report the complete human ABCA1 gene sequence, including 1,453 bp of the promoter, 146,581 bp of introns and exons, and 1 kb of the 3' flanking region. The ABCA1 gene spans 149 kb and comprises 50 exons. Sixty-two repetitive Alu sequences were identified in introns 1-49. The transcription start site is 315 bp upstream of a newly identified initiation methionine codon and encodes an ORF of 6,783 bp. Thus, the ABCA1 protein is comprised of 2,261 aa. Analysis of the 1,453 bp 5' upstream of the transcriptional start site reveals multiple binding sites for transcription factors with roles in lipid metabolism. Comparative analysis of the mouse and human ABCA1 promoter sequences identified specific regulatory elements, which are evolutionarily conserved. The human ABCA1 promoter fragment -200 to -80 bp that contains binding motifs for SP1, SP3, E-box, and AP1 modulates cellular cholesterol and cAMP regulation of ABCA1 gene expression. These combined findings provide insights into ABCA1-mediated regulation of cellular cholesterol metabolism and will facilitate the identification of new pharmacologic agents for the treatment of atherosclerosis in humans.

ATP Binding Cassette Transporter 1↗
PubMed1999

Human ATP-binding cassette transporter 1 (ABC1): genomic organization and identification of the genetic defect in the original Tangier disease kindred.

Tangier disease is characterized by low serum high density lipoproteins and a biochemical defect in the cellular efflux of lipids to high density lipoproteins. ABC1, a member of the ATP-binding cassette family, recently has been identified as the defective gene in Tangier disease. We report here the organization of the human ABC1 gene and the identification of a mutation in the ABC1 gene from the original Tangier disease kindred. The organization of the human ABC1 gene is similar to that of the mouse ABC1 gene and other related ABC genes. The ABC1 gene contains 49 exons that range in size from 33 to 249 bp and is over 70 kb in length. Sequence analysis of the ABC1 gene revealed that the proband for Tangier disease was homozygous for a deletion of nucleotides 3283 and 3284 (TC) in exon 22. The deletion results in a frameshift mutation and a premature stop codon starting at nucleotide 3375. The product is predicted to encode a nonfunctional protein of 1,084 aa, which is approximately half the size of the full-length ABC1 protein. The loss of a Mnl1 restriction site, which results from the deletion, was used to establish the genotype of the rest of the kindred. In summary, we report on the genomic organization of the human ABC1 gene and identify a frameshift mutation in the ABC1 gene of the index case of Tangier disease. These results will be useful in the future characterization of the structure and function of the ABC1 gene and the analysis of additional ABC1 mutations in patients with Tangier disease.

ATP Binding Cassette Transporter 1↗
PubMed1993

Phenotyping. On reaching base camp (1950-1975).

The search for plasma lipoproteins began at the turn of the century. It was not until 1949 that a meeting of the Faraday Society celebrated the separation of the alpha and beta lipoproteins. At that moment, ultracentrifugists in Berkeley were already busily converting "alpha" to high density lipoprotein and "beta" to low density lipoprotein; the modern era of lipoproteins had begun. Over the succeeding 10 years, a quarrel over whether the level of Sf 0-20 or cholesterol was the more powerful risk factor ended with an eclipse of the analytical ultracentrifuge and a surge of interest in the biological side of lipoproteins. The postheparin clearing factor became lipoprotein lipase, and free fatty acids were discovered. In 1960, abetalipoproteinemia and Tangier disease suggested that the apolipoproteins must be specific and spurred a hunt for their number and nature. The first amino acid sequences aroused speculation of "amphipathic helices." By 1970, conversion of hyperlipidemia to five types of hyperlipoproteinemia led to worldwide fascination with electrophoretic patterns, "floating beta," and "the Friedewald formula" as codes for genetic abnormalities leading to early coronary artery disease. A few years later, the appearance of "familial combined hyperlipidemia" confounded the phenotyping, and the discovery of the low density lipoprotein receptor heralded the coming of true genotypes. This is a Bethesda-based story of the "climb to base camp" preceding the joining of molecular biology with the research on lipoproteins, dyslipoproteinemia, and atherosclerosis.

England↗
PubMed1992

The heart in Tangier disease. Severe coronary atherosclerosis with near absence of high-density lipoprotein cholesterol.

Cardiac necropsy findings are described in a 72-year-old man with Tangier disease whose plasma total cholesterol levels averaged 70 mg/dL, low-density lipoprotein cholesterol level was 45 mg/dL, and high-density lipoprotein cholesterol level was 1.4 mg/dL, and who had coronary artery bypass grafting for severe atherosclerotic coronary artery disease. At necropsy, 24 of the 72 (33%) 5-mm segments of the 4 major (right, left main, left anterior descending, and left circumflex) native coronary arteries and 4 of the 27 (15%) 5-mm segments of the saphenous vein aortocoronary bypass conduits were narrowed by more than 75% in cross-sectional area by atherosclerotic plaques. The plaques were composed primarily (91% to 97%) of fibrous tissue. Oil red O staining, polarized light microscopy, and electron microscopy revealed cholesterol deposits in the plaques and in the walls of coronary arteries, saphenous vein grafts, and aorta. Such deposits also were found in foam cells of histiocytic origin, fibroblasts in all four cardiac valves, and in Schwann cells of cardiac nerves.

Aged↗
PubMed1978

Tangier disease: one explanation of lipid storage.

Normal high-density lipoproteins are absent from plasma in Tangier disease, and the disorder is characterized by accumulation of cholesteryl esters in several tissues, particularly those of the reticuloendothelial system. Electron microscopy of the abnormal high-density lipoproteins in the plasma of three patients with Tangier diseases revealed large (68-nm), flattened, translucent particles in all cases. These particles were most abundant in the plasma of the splenectomized patient. Restriction of dietary fat eliminated or drastically reduced the numbers of these particles among the Tangier high-density lipoproteins. Thus abnormal products of chylomicron metabolism that appear to occur in plasma in this disorder may be targets for phagocytosis and may be at least one source of the cholesteryl esters that accumulate in reticuloendothelial tissues in Tangier disease.

Adult↗