10.1 Introduction The cis acting cp er ato riprom dter sites are adacent tothe str ud ural genes Figure 10.2 In Regul atory region Strudural gene(s) negative control, N入入入八N八N八N八NNN八N a trans-acting Genes are on because RN Apolymerase initiatestranscr iption at prom oter repressor binds to the cis-acting NN入入NNN八LZ00020风N operator to turn off transcription RNA In prokaryotes, Sev eralprdeins multiple genes are controlled Genes are tumed off when repressor binds to ope rator Repressor coordinately. 清菜大当 八NN风N凡N八LZ02020020八
Figure 10.2 In negative control, a trans-acting repressor binds to the cis-acting operator to turn off transcription. In prokaryotes, multiple genes are controlled coordinately. 10.1 Introduction
10.1 Introduction Regulatory region prom oter Startpoint Structural genes Prom oter GENE OFF BY DEFAULT N八N八N八N八NNN八N风NN风NN RNA Factors interac with RNA polym erase GENE TURNED ON BY ACTIVATORS 八八入N八风入风风风风风风风风风风风风 RNA Single protein Figure 10.3 In positive control,trans-acting factors must bind to cis-acting sites in order for RNA polymerase to initiate transcription at the promoter. In a eukaryotic system,a structural gene is controlled individually 清萃大兰
Figure 10.3 In positive control, trans-acting factors must bind to cis-acting sites in order for RNA polymerase to initiate transcription at the promoter. In a eukaryotic system, a structural gene is controlled individually. 10.1 Introduction
10.2 Structural gene clusters are coordinately controlled Operon is a unit of bacterial gene expression and regulation,including structural genes and control elements in DNA recognized by regulator gene product(s). 情華大当
Operon is a unit of bacterial gene expression and regulation, including structural genes and control elements in DNA recognized by regulator gene product(s). 10.2 Structural gene clusters are coordinately controlled
10.2 Structural gene clusters are coordinately controlled 公X入NN苏NNN P 1040 82 3510 780 825 mRNA Protein Repressor B-galactosidase P ermeaseTransacetyase Figure 10.4 The lac operon occupies ~6000 bp of DNA.At the left the lacl gene has its own promoter and terminator.The end of the lacl region is adjacent to the promoter,P.The operator,O, occupies the first 26 bp of the long lacZ gene,followed by the 清菜大当 lacY and lac4 genes and a terminator
Figure 10.4 The lac operon occupies ~6000 bp of DNA. At the left the lacI gene has its own promoter and terminator. The end of the lacI region is adjacent to the promoter, P. The operator, O, occupies the first 26 bp of the long lacZ gene, followed by the lacY and lacA genes and a terminator. 10.2 Structural gene clusters are coordinately controlled
10.2 Structural gene clusters are coordinately controlled Startpoint Figure 10.5 Repressor and RNA polymerase -50-40-30-20-1011020 30 bind at sites that Promater overlap around binds RNA polymerase the startpoint of Operator the lac operon. binds repressor 清菜大当
Figure 10.5 Repressor and RNA polymerase bind at sites that overlap around the startpoint of the lac operon. 10.2 Structural gene clusters are coordinately controlled