Pol Ill promoter may be 20.5 RNA polymerase Ill downstrean of the startpoint uses both downstream and upstream promoters Startpoint Promoter Upstream Transcribed region 入AA Figure 20. 5 Deletion analysis shows that the RNA promoter for SS RNA Deletion that removes sequences upstream of genes Is internal promoter allows transcnption to init ate from Initiation occurs a position corresponding to usual startpoint fixed distance( upstream of the promoter. 消当 RNA
Figure 20.5 Deletion analysis shows that the promoter for 5S RNA genes is internal; initiation occurs a fixed distance (~55 bp) upstream of the promoter. 20.5 RNA polymerase III uses both downstream and upstream promoters
20.5 RNA polymerase Il uses both downstream and upstream promoters Startor AMA box A box boxA box MMMMMMAM GE TAT鸟 Figure 20.6 Promoters for RNa polymerase Ill may consist of bipartite sequences downstream of the startpoint, with boxA separated from either boxC or boxB. Or they may consist of separated sequences upstream of the startpoint 筝大1 L(Oct, PSE, TATA
Figure 20.6 Promoters for RNA polymerase III may consist of bipartite sequences downstream of the startpoint, with boxA separated from either boxC or boxB. Or they may consist of separated sequences upstream of the startpoint (Oct, PSE, TATA). 20.5 RNA polymerase III uses both downstream and upstream promoters
20.5 RNA polymerase Il uses both downstream and upstream promoters Type 1 internal promoters 入 MA MNN box A box c boX日 Figure 20.7 TFIIIC TFIIIC Initiation via the internal pol III TFIIIC promoters involves the assembly factors TFⅢB TFIIA and TFIlIc 入八 MM A the initiation factor TFIB and rna polymerase II Pol‖l Pol‖l 消当
Figure 20.7 Initiation via the internal pol III promoters involves the assembly factors TFIIIA and TFIIIC, the initiation factor TFIIIB, and RNA polymerase III. 20.5 RNA polymerase III uses both downstream and upstream promoters
20.6 The startpoint for RNa polymerase II TATA box is a conserved A T-rich septamer found about 25 bp before the startpoint of each eukaryotic rna polymerase II transcription unit; may be involved in positioning the enzyme for correct initiation 消当
TATA box is a conserved A·T-rich septamer found about 25 bp before the startpoint of each eukaryotic RNA polymerase II transcription unit; may be involved in positioning the enzyme for correct initiation. 20.6 The startpoint for RNA polymerase II
Pol ll promoters 20 / TBPis a TB TF口 universal factor TIC RNA polymerase‖l Figure 20.8 Pol I promoters TBP RNA RNA polymerase I polymerases are positioned at all promoters by a Pol ll promote TBP factor that TATA Startpoint contains tBP 测恐规人织 消当 RNA polymerase I
Figure 20.8 RNA polymerases are positioned at all promoters by a factor that contains TBP. 20.7 TBP is a universal factor