Structure of the genes of two homologous intracellularly heterotopic isoenzymes. Cytosolic and mitochondrial aspartate aminotransferase of chicken.

摘要: The genes of mitochondrial and cytosolic aspartate aminotransferase chicken were cloned sequenced. In both nine exons encode the mature enzyme. additional exon for N-terminal presequence that directs into mitochondria is separated by largest intron from rest gene. A comparison two with mouse [Tsuzuki, T., Obaru, K., Setoyama, C. & Shimada, K. (1987) J. Mol. Biol. 198, 21-31; Tsuzuki, (1988) 200, 13-22] reveals closely similar structures: in gene isoenzyme all but one positions are conserved species five introns out placed at same four indicating place before isoenzymes diverged. variant consensus sequence (T/C)11 T(C/T)AG 3' splice site nuclear-encoded proteins, which had been deduced a total 34 [Juretic, N., Jaussi, R., Mattes, U. Christen, P. Nucleic Acids Res. 15, 10,083-10,086], was confirmed including an 22 comparison. position -4 occupied base T 43% 56 appears to be subject special evolutionary constraint this particular group genes. following course evolution proposed. Originating common ancestor, intermediarily evolved separate lineages, i.e. ancestor eukaryotic endosymbiontic cells. When endosymbiosis established, part genome, gene, transferred nucleus. This process probably led conservation certain splicing factors specific proteins. acquired DNA rearrangement. lineage, more slowly than its counterpart.