Expression of δ -aminolevulinate Synthase in Avian Cells: Separate Genes Encode Erythroid-Specific and Nonspecific Isozymes

• Published in: Proceedings of the National Academy of Sciences - PNAS 1989-02, Vol.86 (3), p.792-796
• Main Authors: Riddle, Robert D., Yamamoto, Masayuki, Engel, James Douglas
• Format: Article
• Language: English
• Subjects: 5-Aminolevulinate Synthetase - genetics; Amino Acid Sequence; Amino acids; Animals; Base Sequence; Biological and medical sciences; Chickens; Cloning, Molecular; Complementary DNA; DNA; DNA - blood; DNA - genetics; DNA - isolation & purification; Enzymes; Erythroid cells; Fundamental and applied biological sciences. Psychology; Gene expression; Genes; Isoenzymes - genetics; Library associations; Liver; Liver - enzymology; Messenger RNA; Molecular and cellular biology; Molecular genetics; Molecular Sequence Data; Organ Specificity; Restriction Mapping; Reticulocytes - enzymology; RNA; Sequence Homology, Nucleic Acid
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.86.3.792

A controversy has existed in the literature for the past several years regarding the number of vertebrate genes encoding the mitochondrial protein that initiates the first step in heme biosynthesis, δ -aminolevulinate synthase [ALAS; succinyl-CoA:glycine C-succinyltransferase (decarboxylating), EC 2.3.1.37]. By analysis of chicken ALAS cDNA clones isolated from both liver and erythroid cells, we show that at least two separate genes encode ALAS mRNAs. These experiments show that (i) two different genes encode the ALAS isozymes found in erythroid and in liver tissues, and (ii) while the product of the erythroid gene (ALASE) is expressed exclusively in erythroid cells, the hepatic form of the enzyme is expressed ubiquitously, suggesting that this is the nonspecific form (ALASN) found in all chicken tissues.