Nucleotide sequence analysis of murine 21-hydroxylase genes: Mutations affecting gene expression

Academic Article


  • Steroid 21-hydroxylase [21-OHase; steroid 21-monooxygenase; steroid, hydrogen-donor:oxygen oxidoreductase (21-hydroxylating); EC] is a cytochrome P-450 enzyme required for the adrenal synthesis of mineralocorticoids and glucocorticoids. The gene encoding this protein is present in two copies (21-OHase A and B) in the S region of the murine major histocompatibility complex. Previous studies utilizing gene-specific oligonucleotide probes and gene transfer showed that only the 21-OHase A gene is expressed in the BALB/c mouse. Here, we present the complete primary structures of both BALB/c 21-OHase encoding genes. Comparison of the nucleotide sequences defines a deletion of 215 nucleotides spanning the second exon of the 21-OHase B gene; other nucleotide changes in the 21-OHase B gene introduce frame shifts and premature termination codons. Southern blot analysis of C57BL/6 and DBA/2J mice indicates that a similar deletion is present in these strains; however, the C3H/HeJ strain is a structural variant. A hybrid gene composed of the 21-OHase B promoter placed 5' of the 21-OHase A structural sequences was efficiently transcribed following transfection into Y1 adrenocortical tumor cells. These findings demonstrate that the 21-OHase B gene promoter is functional and suggest that mutations within the 21-OHase B structural gene are responsible for its lack of expression.
  • Digital Object Identifier (doi)

    Author List

  • Chaplin DD; Galbraith LJ; Seidman JG; White PC; Parker KL
  • Start Page

  • 9601
  • End Page

  • 9605
  • Volume

  • 83
  • Issue

  • 24