1. Alternate sigma factor usage: controls selective transcription
Ways to Regulate Transcription
Alternate sigma factor usage: controls selective transcription
of entire sets of genes
vegetative
(principal s)
s70 +1
צמיחה
(16-19 bp)
(5-9 bp)
TTGACA
TATAAT A
heat shock +1
s32
(13-15 bp)
(5-9 bp)
CNCTTGA
CCCATNT A +1
nitrogen
starvation
s60
(6 bp)
(5-9 bp)
CTGGNA
TTGCA A
התרגיל ביום חמישי זה – !

2. טרנסקריפציה באוקריוטים

4. Pre-mRNA
* microRNAs (miRNA) RNA molecules of about 21–23 nucleotides in length, which regulate gene expression. are processed from primary transcripts known as pri-miRNA.

6. 5’UTR
3’UTR

7. בתאי כבד בעכבר

9. RNA polymerase

10. מיקום +1
רמה נמוכה (בזלית)
יעילות ותדירות
אינטרונים E S RE

13. אין אחידות במיקום וברצפי הבקרה בין גנים שונים.

14. שלבי הטרנסקריפציה
Initiation
Elongation
Termination

18. קומפלקס פרה-איניציציה
יציבות ותדירות
יצירת קומפלקס זה
קובעת את כמות וקצב
סינטזת ה-RNA

20. אופן אקטיבציה של טרנסקריפציה בתאים אוקריוטים

21. Stages in Initiation of Transcription
Bacterial transcription
Closed complex: holoenzyme+promoter
Open complex (DNA melting, not need ATP)
Abortive transcripton
Productive initiation
Transcribe past +9
Sigma dissociates
Elongation
Eukaryotic transcription
Preinitiation complex (PIC) assembly
PIC activation (DNA melting, needs ATP)
Abortive transcription
Productive initiation
CTD phosphorylated
Promoter clearance
Elongation

22. initiation

23. Elongation
NTPs

24. TERMINATION RNA polymerase meets the terminator
Terminator sequence: AAUAAA
RNA polymerase releases from DNA
Prokaryotes-releases at termination signal
Eukaryotes-releases base pairs after termination signal

29. קומפלקס האלונגציה

30. transcription

32. Transcription regulation

39. Gene expression
Gene expression

41. Basics of cell biology:development
Fertilized egg

42. Basics of cell biology:development
Cells differentiation
is due to different gene
Switches going on and off
These cells are different
because they express a
subset of their 24,000 genes

43. Gene
Promoter
To specify a new cell: place it in the right environment or

44. EGF
Hedgehog
Wnt
Gene
Promoter
Retinoic acid
FGF
HGF
To specify a new cell: place it in the right environment or
Substitute drugs/proteins for environment
Mophogens

45. Chromosome localization in interphase
In interphase, chromosomes appear
to be localized to a sub-region of the
nucleus.