Transcription of the bovine adrenodoxin gene produces two species of mRNA of which only one is translated into adrenodoxin.
The 5'-end of the bovine adrenodoxin gene contains unique structural characteristics. Exons 1 and 2 appear to encode different presequences for this mitochondrial precursor protein. However, exon 1 contains a stop codon (TAA) in place of amino acid 15. Thus, while two species of bovine adrenodoxin mRNA arise from a single gene, only the abundant mRNA species (90%) is translated into the adrenodoxin precursor which contains the presequence encoded by exon 2. The minor mRNA species (10%) contains the sequence encoded by exon 1 and cannot be translated into an adrenodoxin precursor. Presumably the sequence within exon 2 is removed from this minor mRNA species by alternative splicing. Furthermore, the initiation of transcription of the major adrenodoxin mRNA (exon 2) lies within intron 1 of this unusual gene, while that for the other mRNA (exon 1) lies in the 5'-flanking region. Thus, the adrenodoxin gene is the first example of a gene encoding a mitochondrial protein which falls into the category of genes having alternate promoters utilizing a pattern of alternative splicing.
Kagimoto
M
M
Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas 75235.
Kagimoto
K
K
Simpson
E R
ER
Waterman
M R
MR
D000325:Adrenodoxin / Q000235:genetics*; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002417:Cattle; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics; D005091:Exons; D005796:Genes; D009693:Nucleic Acid Hybridization; D011061:Poly A / Q000235:genetics; D014176:Protein Biosynthesis; D012313:RNA / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics*; D014158:Transcription, Genetic
D012333:RNA, Messenger; D000325:Adrenodoxin; D011061:Poly A; D012313:RNA; D004247:DNA