Transcriptional Regulation: Control by; - a regulatory region of DNA, sequences - gene regulatory proteins Fig.9-3 Double-helical structure of DNA, major.

Transcriptional Regulation:Control by;- a regulatory region of DNA, sequences- gene regulatory proteins

Fig.9-3 Double-helical structure of DNA, major and minor grooves on the outside of DNA

Fig.9-9 The binding of a gene regulatory protein to the DNA major groove

Fig.9-10 The DNA-bindinghelix-turn-helix motif,A.carboxyl-terminal called recognition helix.B. helix fits into the DNA major groove

Fig.9-11 Some helix-turn-helix DNA-binding proteins. All of the proteins bind DNA as dimers

A. B.

Fig.9-18 A leucine zipper dimer bound to DNA.

Fig.9-19 Heterodimerization of leucine zipper proteina can alter their DNA-binding specificity.- 1&2= homodimers bind to symmetric DNA sequences- 3= two diff. Monomer combine to form a heterodimer

Fig.9-23 DNA affinity chromatography

Eucaryotic Transcriptional Regulation:

Transcription Controls:1. Gene Control Region2. Gene Activator Protein3. Gene Repressor Protein4. Gene Regulatory Protein5. DNA Methylation

Post-Transcription Controls:1. Transcription Attenuation2. Alternative RNA Splicing3. Changed Site of RNA Transcript Cleavage4. RNA Editing

Transcription Controls:1. Gene Control Region - initiate gene transcription - regulate the rate at which initiation occur - GCR consists of Promoter, Regulatory sequence

Transcription Controls:2. Gene Activator Protein - accelerate the assembly of General Transcription Factors

Fig. 9-35 The modular structure of a gene activator protein, activation domain & DNA-binding domain

Fig. 9-50 One model to explain the displacement of nucleosomes during the initiation of transcription in euc.

Transcription Controls:3. Gene Repressor Protein - Inhibit transcription in various ways

Transcription Controls:4. Gene Regulatory Protein - proteins form complexes for creating elaborate switches to control transcription

Fig. 9-38 Euc. Gene regulatory proteins often assemble into small complexes on DNA.A. nature & function of the complexes,form depending on the specific DNA seq.B. one complex activates gene transc., another represses transcription.

Fig. 9-46 Some ways in which the activity of gene regulatory proteinsis regulated in eucaryotic cells.

Transcription Contrils:5. DNA Methylation - inhibit transcription

Fig.9-70 The CG islands surrounding the promoter in three mammalian housekeeping genes.- CG islands, ~40,000 genes- ~1,000-2,000 nts. Pairs long- surrounding the Pormoters, called housekeeping genes, demethylated

Post-Transcription Controls:- operate after RNA Pol has bound to the gene’s Promoter and begun RNA synthesis.

1. Transcription Attenuation2. Alternative RNA Splicing3. Changed Site of RNA Transcript Cleavage4. RNA Editing

Post-Transcription Controls:1. Transcription Attenuation

In Bacteria:By - antitermination factors - switch the Sigma factors

Post-Transcription Controls:2. Alternative RNA Splicing - produce different forms of mRNA

Optional exon

Optional intron

Mutually exclusive exons

Internal splice site

Fig.9-74 Negative and Positive Control of Alternative RNA Splicing.A. Negative Control, Repressor Protein binds to the primary RNA tranc.B. Positive Control, splicing machinery unable to remove a intron without an activator protein.

Post-Transcription Controls:3. Changed Site of RNA Transcript Cleavage

Post-Transcription Controls:4. RNA Editing