Isolation and Characterization of the Bovine Corticotropin/β‐Lipotropin Precursor Gene

Abstract

The entire bovine corticotropin/β‐lipotropin precursor gene has been isolated as a set of overlapping genomic DNA fragments which extend over a length of approximately 17000 base pairs. Restriction mapping of the cloned DNA fragments and nucleotide sequence analysis of the whole mRNA‐coding segments and their surrounding regions have established that the corticotropin/β‐lipotropin precursor gene is approximately 7300‐basepairs long and contains two intervening sequences; one with an approximate length of 4000 base pairs is located within the segment encoding the 5′‐untranslated region of the mRNA, and the other with an approximate length of 2200 base pairs interrupts the protein‐coding sequence near the signal peptide region. Sequence analysis of more than 200 base pairs preceding the proximal end of the corticotropin/(f‐lipotropin precursor gene has revealed a ‘Hogness box’ and a variant of the model sequence as well as palindrome structures as observed in other eukarvotic genes. Furthermore, some sequence similarities in the 5′‐flanking region are found between the corticotropin/β‐lipotropin precursor gene and the mouse α‐globin and β‐globin genes, all of which are negatively regulated by glucocorticoids. At least four homologous repetitive sequences are distributed at 3000–5000‐base‐pair distances in the corticotropin/β‐lipotropin precursor gene region; two such sequences are located in the 5′‐flanking region, and one within each intervening sequence. Blot hybridization analysis of bovine pituitary nuclear RNA has indicated that the entire corticotropin/β‐lipotropin precursor gene 1S transcribed into a primary hnRNA product, which is then spliced to forth the mature mRNA. Copyright © 1981, Wiley Blackwell. All rights reserved