Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../...
-
Upload
benjamin-harrell -
Category
Documents
-
view
230 -
download
7
Transcript of Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../...
![Page 1: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/1.jpg)
Part 3
Gene expression (Ⅰ)transcription
Http : //web.umr.edu/.../ 331figures.html
![Page 2: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/2.jpg)
Summary for Transcription
the Recognization of template ↓
Initiation↓
Pass the promoter↓
Elongation↓
Termination
![Page 3: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/3.jpg)
Ⅰ. Transcription in Prokaryote
Ⅱ. Transcription in Eucaryote
Ⅲ. Products of transcription
![Page 4: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/4.jpg)
Ⅰ. transcription in ProkaryoteIntroduction:• RNA polymerase• Promoter • Initiation and
termination of transcription
![Page 5: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/5.jpg)
RNA polymerase
核心酶
σ 因子
![Page 6: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/6.jpg)
Function of subunit:
α : combine to the promoter, unwind the double-strand
β : for the nucleotide’s combining in initiation and elongation process
β’ : recognize and combine to the template ,unspecifically
σ : recognize and combine to the template specifically
ω : unkown
![Page 7: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/7.jpg)
Promoter
• -10 signal (TATA box,Pribnow box)
• -35 signal
• transcription start site
![Page 8: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/8.jpg)
TATAATTGACA
-35 box
+1
-10 box
-40 ~-30
转录起点
上游
upstream下游
downstream
原核生物的启动子
17+1bp
-10 ~ -7
![Page 9: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/9.jpg)
Initiation
The process of transcription initiation, with every subunit of the RNA polymerase making function orderly ,is from the template being recognized and bound to the first nucleotide residue being transcribed on the start site.
![Page 10: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/10.jpg)
+1
+1
+1
+1
-10
-10
-10
-10
-35
-35
-35
-35
β’
σ
α
β
脱落的 σ ATP or GTP
1
2
3
4
![Page 11: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/11.jpg)
![Page 12: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/12.jpg)
Termination
Two different pattern: ρ- independent termination
ρ –dependent termination
1.reverse repeat with GC rich
2.poly (A) following the GC rich se
quence directly in template
ρ factor:
(1) moves along the nascent RNA towards the transcription complex
(2) Hydrolyzes the ATP
(3) Helicase
![Page 13: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/13.jpg)
不依赖ρ因子的终止子
![Page 14: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/14.jpg)
依赖ρ因子的终止子
![Page 15: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/15.jpg)
Ⅱ. Transcription in Eucaryote
Introduction:• RNA polymerase• Promoter and transcription initiation• Termination of transcription• Post-transcriptional Processing
![Page 16: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/16.jpg)
RNA polymerase
Multi-subunit enzyme
Contain: two large subunits whose MW are more than 1*105 several small subunits which may be the same in 2 o
r 3 kinds of RNA polymerase
different RNA polymerase is with responsibility for different gene
![Page 17: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/17.jpg)
Polymerase
location Respondent gene
RNA polymerase Ⅰ
Nucleoli ( 核仁 )
rRNA gene cluster (except 5s rRNA gene)
RNA polymerase Ⅱ
nucleoplasm (核质)
all genes encoding protein, some encoding U-RNA
RNA polymerase Ⅲ
nucleoplasm (核质)
5s rRNA gene, tRNA gene
RNA polymerase and its respondent gene
![Page 18: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/18.jpg)
rRNA gene cluster (Pol gene )Ⅰ
18s-5.8s-28s
18s-5.8s-28s
18s-5.8s-28s
18s-5.8s-28s
promoterPromoterrepeat
Promoter repeat
60/81bp repeatNTS
![Page 19: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/19.jpg)
Typical mRNA gene (pol gene)Ⅱ
Coding region5’- 侧
翼 3’ - 侧翼
5’UTR
3’UTR
EXON EXON EXON EXON
![Page 20: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/20.jpg)
Pol geneⅢ
+1
内启动子
A box
+50~+65
C box
+81~+99
5s rRNA gene
![Page 21: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/21.jpg)
tRNA gene
+1
内启动子
A box B box
D-loop TψC-loop
![Page 22: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/22.jpg)
Promoter & transcriptional initiation
• Promoter : A sequence region which promote the initiation of transcription
• Transcriptional initiation
![Page 23: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/23.jpg)
RNA pol promoterⅠ
+1
+6-31-100
UCE:50~80bp Core promoter Pre-rRNA gene
Enhance transcription
Essential for transcription
![Page 24: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/24.jpg)
Initiation of pol gene’s transcriptionⅠUBFUBF
SL1POL Ⅰ
NOTE: UBF----upstream binding factor
SL1----selectivity factor
![Page 25: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/25.jpg)
RNA Pol PromoterⅡ
Consist of:1) Transcription start-site: A or G
2) TATA box: determine the exact starting
3) UAS (UPE): determine the frequency of initiation
4) Enhancer : enhance the frequency of initiation
![Page 26: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/26.jpg)
ATATAACCAATGCCACACCC
或
GGGCGGG
+1
转录起点TATA boxCAAT boxGC box增强子
UPE or UAS
Py A Py
promoter model
-35 ~ -25-80 ~ -70-110 ~ -80
![Page 27: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/27.jpg)
Enhancer in SV40
![Page 28: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/28.jpg)
72bp ,分 A 、 B 、 C三区
A C B
-200-220-232-250 -248-271
两个核心 A
或 核心 A+ 部分A
核心 C+TCⅡ
Sph +SphⅡ Ⅰ
三个主区相互作用发挥增强转录的作用
The enhancer’s architecture in SV40
![Page 29: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/29.jpg)
Transcription initiation of pol geneⅡ
Transcription factors recognize and bind to the promoter to assemble an initiation complex(basal transcriptional initiation complex or activated transcriptional initiation complex)
![Page 30: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/30.jpg)
Basal transcriptional initiation complex
![Page 31: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/31.jpg)
Activated transcriptional initiation complex
TATA
ⅡAⅡB
ⅡF
ⅡE
ⅡH
TBPTAFs
PolⅡCBPUSA
Mediator
![Page 32: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/32.jpg)
AAAAAATAAA
3’
加尾信号 Poly(A)
真核生物中与转录终止有关的序列
Termination
终止
0.5~2 kb15~30 bp
![Page 33: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/33.jpg)
Termination of transcription
In eucaryote, the transcription termination is different from that in prokaryote.
polyadenylation signal & Poly(A) addition site: the terminus signal but not the terminator
Terminate downstream
![Page 34: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/34.jpg)
TF CⅢ
Pol promoter & transcriptioⅢn initiation
+1内启动子
A box
+50~+65
C box
+81~+99
5s rRNA gene
TF BⅢ
Pol Ⅲ
TF AⅢ
![Page 35: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/35.jpg)
内启动子
A box B box
tRNA gene
D-loop TψC-loop
+1
TF CⅢTF BⅢ
Pol Ⅲ
![Page 36: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/36.jpg)
Post-transcriptional Processing
• tRNA processing
• rRNA processing
• mRNA processing
![Page 37: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/37.jpg)
rRNA processing
ITS1 ITS2ETS1 ETS2
RNase
RNase
RNase
![Page 38: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/38.jpg)
tRNA processing
![Page 39: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/39.jpg)
mRNA processing
• 5’ capping• 3’ polyadenylation• splicing : primary product: hnRNA ( intron, exon)
• RNA editing and modification
mRNA
POSTTRANSCRIPTIONAL PROCESS
![Page 40: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/40.jpg)
5’ capping
m7G 5’-p-p-p-5’AN
m7G ppp p-p-p-5’ A N
腺苷酸转移酶甲基转移酶
Cap 0
Cap 1
Cap 2
5’ , 5’ – 磷酸二酯键
m7G 5’-p-p-p-5’Am2’N
m7G 5’-p-p-p-5’Am2’Nm2’
GTP 尿苷酸 -7- 甲基转移酶
![Page 41: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/41.jpg)
3’ polyadenylation
AAUAAA CASTOP15~30 bases
0.5~2kb
polyadenylation
Cleavage site
Poly(A)addition site
Pre-mRNA
![Page 42: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/42.jpg)
splicing Interrupted gene: exon & intron Classes of intron:
» 主要的内含子 : 5 ’GU……AG 3’» 次要的内含子 : 5’ AU……AC 3’» Ⅰ 类内含子» Ⅱ 类内含子» Ⅲ 类内含子» 双内含子» tRNA 前体中的内含子
Introns are spliced in posttranscription processing :见课本 P92 、 94 、 95
Alternative splicing: Reference: “regulation of eucaryote gene expression”
![Page 43: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/43.jpg)
主要的内含子
exon exon
AGGUAAGU PyPyPyPyPyPyNCAG
5’ 剪接位点
3’剪接位点
多聚嘧啶系列
CURAY
分支点序列
![Page 44: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/44.jpg)
RNA modification
Modification:specific chemical modification. 甲基化 去氨基 硫代 积极的同分异构化 二价键的饱和化 核苷酸的替代
![Page 45: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/45.jpg)
Methylation guided by snoRNA
![Page 46: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/46.jpg)
RNA editing
Reference: “regulation of eucaryote gene expression”
Editing: to alter the coding information by change the mRNA sequence.
![Page 47: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/47.jpg)
Products of transcription
• In prokaryote short half-life:Multi-cistronStarting codon & SD sequence• In eucaryote 5’ cap3’ tailPrimary products must be peocessed to pro
duce mature mRNA
![Page 48: Part 3 Gene expression ( Ⅰ ) transcription Http : //web.umr.edu/.../ 331figures.htmlweb.umr.edu/.../ 331figures.html.](https://reader036.fdocuments.in/reader036/viewer/2022062518/5697bf951a28abf838c909b1/html5/thumbnails/48.jpg)
SD sequence
AUG~10bases
UAAGGAGGU:complementary with 16s rRNA
5’
The site for ribosome binding