BMD RES 5HA Lecture Notes - Lecture 4: Dna-Binding Domain, Tata Box, Heterochromatin
• Inhibiting an inhibition: disinhibition
(repressor binds) Leg dev. Antp repressor
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• How do we control gene expression?
- Gene expression is complex and controlled by proteins
- Subset of proteins go back & regulate gene expression
- General name for proteins involved in gene regulation: transcription factors = proteins that
mediate early steps of gene expression
• Enhancer: DNA sequence element that binds a specific transcription factor to activate
transcription
• Promoter: DNA sequence element proximal to beginning of coding sequence that directs
initiation
- Proximal:
➢ Promoter tells RNA pol where to begin transcription
➢ so do’t eed to tasie stuff that do’t get translated
- RNA pol binds to TATA box
• Silencer (sequence) binds repressor (protein)
• Activator: transcription factor turning on/enhances transcription of gene
• Insulator: DNA elements recruit proteins & help regulate chromatin structure
- If a gene is surrounded by heterochromatin, sometimes can be silenced by heterochromatin
- If want that gene open, have insulator elements that help keep chromatin away
- Thus it protects the DNA inside
genes: the two-component model
• Gees do’t just ode fo poteis
- The coding regions store info about how to make proteins
- Regulatory regions store info about how to express them (e.g. enhancer)
• production of an active protein in a cell is regulated: by multiple mechanisms functioning in the
nucleus and in the cytoplasm.
• Determining how a large number of uncharacterized genes functions biologically is typically
referred to as: functional genomics
• Activator protein has two domains (functional regions)
- DNA binding domain
- Activation domain
• Enhancer -> eye-specific activator (specificity) -> gene X is only expressed in the eye
- But it ould e peset i ee ell, though does’t hae to e atie
- Enhancer & activator separate from downstream gene
If swap out the gene with another gene, it would still be expressed only in the eye, bc still
under control of eye-specific enhancer
• Ho do atiatos fid ehaes?
By chance -> increase possibility?
- Increase concentration (make more/increase nucleus concentration (Nucleus Localization
Sequence, tag))
- Chromatin: selectively change where is open -> change the gene that can be interacted with
- Whethe potei is oud ith DNA is f of tie iteatig does’t ea idig
- H bonds stabilize protein: DNA interactions <- complementary sequence
➢ Maximize number of H bonds -> stay for longer
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Document Summary
Inhibiting an inhibition: disinhibition (repressor binds) leg dev. Gene expression is complex and controlled by proteins. Subset of proteins go back & regulate gene expression. Promoter tells rna pol where to begin transcription. So do(cid:374)"t (cid:374)eed to t(cid:396)a(cid:374)s(cid:272)(cid:396)i(cid:271)e stuff that do(cid:374)"t get translated. Rna pol binds to tata box: silencer (sequence) binds repressor (protein, activator: transcription factor turning on/enhances transcription of gene. Insulator: dna elements recruit proteins & help regulate chromatin structure. If a gene is surrounded by heterochromatin, sometimes can be silenced by heterochromatin. If want that gene open, have insulator elements that help keep chromatin away. Thus it protects the dna inside genes: the two-component model: ge(cid:374)es do(cid:374)"t just (cid:272)ode fo(cid:396) p(cid:396)otei(cid:374)s. The coding regions store info about how to make proteins. Activation domain: enhancer -> eye-specific activator (specificity) -> gene x is only expressed in the eye. But it (cid:272)ould (cid:271)e p(cid:396)ese(cid:374)t i(cid:374) e(cid:448)e(cid:396)(cid:455) (cid:272)ell, though does(cid:374)"t ha(cid:448)e to (cid:271)e a(cid:272)ti(cid:448)e.