passages.id: split_6_test_2666_passage
passages.type: progene_text
passages.text: Luciferase reporter constructs demonstrate that the first two ICA1 exon promoters reciprocally stimulate luciferase expression within islet - ( RIN 1046 - 38 cells ) and brain - derived ( NMB7 ) cells in culture ; the exon A promoter exhibits greater activity in islet cells , whereas the exon B promoter more efficiently activates transcription in neuronal cells .