passages.id: split_4_validation_1121_passage
passages.type: progene_text
passages.text: The cDNA for the sea urchin mitochondrial D-loop - binding protein ( mtDBP ) , a 40 kDa protein which binds two homologous regions of mitochondrial DNA ( the D - loop region and the boundary between the oppositely transcribed ND5 and ND6 genes ) , has been cloned .