Analyze how specific documents activate the features of the SAE. Select a dataset, a run and a document to begin.
1526
Details List
Document Content
Evolution of the apolipoproteins. Structure of the rat apo-A-IV gene and its relationship to the human genes for apo-A-I, C-III, and E.
We have determined the nucleotide sequence of the rat apolipoprotein (apo-) A-IV gene and analyzed its structural and evolutionary relationships to the human apolipoprotein A-I, E, and C-III genes. The rat A-IV gene is 2.4 kilobases in size and consists of three exons (142, 126, and 1157 base pairs) interrupted by two introns (277 and 673 base pairs). The 5'-nontranslated region and most of the signal peptide are encoded by the first exon. Thus, the apo-A-IV gene lacks an intron in the 5'-nontranslated region of its mRNA in contrast to all other known apolipoprotein genes. Sequences coding for amphipathic docosapeptides span both the second and third exons of the rat A-IV gene. We demonstrate that this is also true for the human apolipoprotein genes. This gene family seems to have evolved by the duplication of an ancestral minigene that resulted in the formation of two exons. Thereafter, evolution of these sequences was dominated by intraexonic amplification of repeating units coding for amphipathic peptides. Sequence divergence of these repeats resulted in the functional differentiation of the apolipoproteins. However, conservation of the fundamental amphipathic pattern allowed members of this protein family to retain their lipid-binding properties.
Similar Documents
-
#378 0.426Prevention of in vitro low-density lipoprotein ox…
-
#837 0.398Histone Variants and Disease. In eukaryotes, the …
-
#863 0.384The pleiotropic effects of erythropoietin in the …
-
#605 0.383Pathway length and evolutionary constraint in ami…
-
#320 0.383Bend and helical twist associated with a symmetri…