When isolated from rapidly growing cells , the assembly contained ribonucleic acid ( RNA ) polymerase ( pol ) 1 , and some of its transcription factors like TATA binding protein ( TBP ) , Rrn3p , Rrn5p , Rrn7p , and Reb1p along with rRNA processing factors , like Nop1p , Cbf5p , Nhp2p , and Rrp5p . ^^^