Nucleotide sequence of rat steroidogenic acute regulatory protein complementary DNA.

The steroidogenic acute regulatory (StAR) protein is a key regulator for the steroidogenesis in acute response to trophic hormone. A rat complementary DNA of the StAR protein was cloned and its complete nucleotide sequence was determined. The deduced amino acid sequence of the clone has an additional 86 amino acid stretch at amino terminus when it was compared with those sequences in other species. The other part of the amino acid sequence has 94% identity to mouse StAR protein sequence. Three transcripts (1.3 kb, 1.6 kb, and 3.5 kb) which are hybridizing to the clone were detected in testis, ovary and adrenal gland. When the cDNA was expressed in COS1 cells, 30 kDa and 47 kDa proteins specific to the anti-StAR antibody were detected.