passages.id: split_4_test_2523_passage
passages.type: progene_text
passages.text: Because steroidogenic factor 1 ( SF-1 ) , the transcription factor required for expression of P450scc in the adrenals and the gonads , is not expressed in the placenta , we hypothesized that placenta - specific nuclear factor(s) ( PNF ) assumes the role of SF-1 by binding to the same promoter region that harbors the SF-1 recognition site in the P450scc gene .