The chicken progesterone receptor A and B isoforms are products of an alternate translation initiation event.
The chicken progesterone receptor A and B proteins differ by an additional 128 amino acids located at the N terminus of the B protein. Using site-directed mutagenesis, we demonstrate that these two proteins arise by alternate initiation of translation from two in-phase AUG codons located on a single mRNA transcript. Both proteins are transcriptionally active in terms of their ability to activate a progesterone-responsive target gene. These results suggest a functional significance for evolutionary conservation of two forms of this steroid receptor.
Conneely
O M
OM
Department of Cell Biology, Baylor College of Medicine, Houston, Texas 77030.
Kettelberger
D M
DM
Tsai
M J
MJ
Schrader
W T
WT
O'Malley
B W
BW
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002645:Chickens; D005786:Gene Expression Regulation; D005796:Genes; D008969:Molecular Sequence Data; D010442:Peptide Chain Initiation, Translational; D011487:Protein Conformation; D012333:RNA, Messenger / Q000378:metabolism; D011980:Receptors, Progesterone / Q000096:biosynthesis* / Q000235:genetics / Q000502:physiology; D014158:Transcription, Genetic
D012333:RNA, Messenger; D011980:Receptors, Progesterone