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

Proc Natl Acad Sci U S A. 1986 Dec;83(24):9601-5. doi: 10.1073/pnas.83.24.9601.


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.

Publication types

  • Comparative Study
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Chromosome Deletion
  • Gene Expression Regulation
  • Genes
  • Mice
  • Mutation
  • Promoter Regions, Genetic
  • Sequence Homology, Nucleic Acid
  • Steroid 21-Hydroxylase / genetics*
  • Steroid Hydroxylases / genetics*


  • Steroid Hydroxylases
  • Steroid 21-Hydroxylase

Associated data

  • GENBANK/M15008
  • GENBANK/M15009