nactive Cond ition 21. 3 There are many Protein synthesized No protein Homeoproteins types of DNA-binding Protein phosphorylated domains A HSTF Inactive prots Protein de phosphorylated Figure 2 1.2 The activity of a Inactive protein Ligand binding regulatory transcription 八 factor may be controlled by receptors Inactive prot: synthesis of protein. Cleavage to release active factor covalent modification of 八N protein, ligand binding, or Membran Releas inhibitor binding of inhibitors that 八A sequester the protein or Inactive prot NFk日 affect its ability to bind to nhi bitor DNA 八A 消当 I nactive part
Figure 21.2 The activity of a regulatory transcription factor may be controlled by synthesis of protein, covalent modification of protein, ligand binding, or binding of inhibitors that sequester the protein or affect its ability to bind to DNA. 21.3 There are many types of DNA-binding domains
21. 3 There are Mechanism of facto many types of DNA Jun Fos p65-p50 dimer binding domains NF↓B 八AAA AP-1 may b regulated by Phosphorylation of ↓m ↓ Figure 28.19 Oncogenes - kB releases NF-k日 that code for transcription factors have mutations that Inactivate transcription Function of oncogenic factor (v-erbA and possibly v-o V-Rel has lost regions needed to stay in cytoplasm rel) or that activate transcription(v-jun and vvv wvoy V-IOS v-Rel may prevent p65/p50 fom v-Jun and v-Fos may activate target v-ErbA cannot activate orming dimer andor activating genes without responding to usual transcription, and also inhibits transcription 消当
Figure 28.19 Oncogenes that code for transcription factors have mutations that inactivate transcription (v-erbA and possibly vrel) or that activate transcription (v-jun and v-fos). 21.3 There are many types of DNAbinding domains
21. 4 A Zinc finger motif is a DNA-binding domain o呀pQ zn t+ oo②o Figure 21.3 Transcription factor SPl has a series of three zinc fingers, each with a characteristic pattern of cysteine and histidine residues that constitute the zinc-binding site 请莘大
Figure 21.3 Transcription factor SP1 has a series of three zinc fingers, each with a characteristic pattern of cysteine and histidine residues that constitute the zinc-binding site. 21.4 A zinc finger motif is a DNA-binding domain
21. 4 A Zinc finger motif is a DNA-binding domain 0● Figure 21. 4 Zinc ● fingers may form OoO a-helices that Forms Forms B-sheeto-hellx insert into the major groove associated withβ sheets on the other side 请莘大
Figure 21.4 Zinc fingers may form a-helices that insert into the major groove, associated with bsheets on the other side. 21.4 A zinc finger motif is a DNA-binding domain
21 4A zinc finger motif is a ○ ● ○ DNA-binding domain ooO +自 90000 OO Figure 21. 5 The first finger of a DNA binding Dimerization steroid receptor controls specificity of dNA-binding (positions shown in red); the second finger controls specificity of dimerization(positions shown in blue). The expanded view of the first finger shows that ■■■■■■ discrimination between GRE and Glucocorticoid Estrogen ERE target sequences rests on specificity spec ificity two amino acids at the base Same sequence in both receptors lO Different sequence in each receptor 请莘大
Figure 21.5 The first finger of a steroid receptor controls specificity of DNA-binding (positions shown in red); the second finger controls specificity of dimerization (positions shown in blue). The expanded view of the first finger shows that discrimination between GRE and ERE target sequences rests on two amino acids at the base. 21.4 A zinc finger motif is a DNA-binding domain