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BIOL 142 Lecture Notes - Lecture 23: Prokaryote, Mutation, Intron

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cyankoala19
7 May 2018
School
Emory University
Department
Biology
Course
BIOL 142
Professor
Abreu

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Biology'142-'Lecture'23-'Eukaryotic'Gene'Regulation'and'Evolution'
'
Transcription'is'controlled'by'the'interaction'of'regulatory'proteins'with'variable'regulatory'
elements!
• DNA!->!methylated!->!closed!state!!
• DNA!->!acylation!->!open!state!!
• All!eukaryotic!genes!have!a!common!promoter!and!variable!regulatory!elements!
o All!eukaryotic!promoters!are!bound!by!the!TATA-binding!protein!at!the!TATA!box!
o Occurs!at!the!beginning!of!the!gene!and!is!the!site!where!RNA!polymerase!begins!
transcription!
o Downstream!is!the!gene!itself!(made!of!exonerated!and!introns)!
o Promoter-proximal!elements!are!upstream!of!promoter,!and!have!unique!
specific!genes!
§ Pro-transcription,!have!regulatory!effects!on!the!gene!
• Eukaryotic!genes!have!enhancers!and!positive!regulatory!control!elements!
o Enhancers!can!be!100,000!or!more!bases!from!the!promoter,!in!introns,!or!5’!to!
3’!flanking!sequences!
§ Different!enhancers!are!associated!with!different!genes!
§ Activator!proteins!bind!enhancers!and!strongly!stimulate!transcription!
complex!
§ There!can!be!many!different!enhancers!
o Silencers!are!negative!control!element,!and!repress!rather!than!activate!
expression!!!
§ Silencers!bind!proteins!(“repressors”)!and!turn!off!expression!!
§ Note:!these!are!similar!to!the!operators!in!prokaryotic!cells!
• Basal!transcription!factors:!the!bare!minimum!needed!to!do!transcription!(ex.!RNA!
polymerase)!
• Different!cell!types!express!different!genes!because!they!contain!different!regulatory!
proteins!
o Extracellular!signals!trigger!cell-specific!gene!expression!
o Activation!of!specific!regulatory!proteins!by!extracellular!signals!leads!to!certain!
proteins!being!provided!only!in!certain!types!of!cells!
!
Classes'of'proteins'that'bind'to'regulatory'sequences'of'eukaryotic'genes'
• Basal!transcription!factors!!
o They!interact!with!the!promoter!and!are!not!restricted!to!particular!cell!types!!
o Required!for!transcription,!but!do!not!regulate!gene!expression!
o Example:!RNA!Polymerase!
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Document Summary

Biology 142- lecture 23- eukaryotic gene regulation and evolution. Pro-transcription, have regulatory effects on the gene: eukaryotic genes have enhancers and positive regulatory control elements, enhancers can be 100,000 or more bases from the promoter, in introns, or 5" to. Different enhancers are associated with different genes. Activator proteins bind enhancers and strongly stimulate transcription complex. There can be many different enhancers: silencers are negative control element, and repress rather than activate expression. Silencers bind proteins ( repressors ) and turn off expression. Note: these are similar to the operators in prokaryotic cells: basal transcription factors: the bare minimum needed to do transcription (ex. Rna processing: rna splicing is a form of transcriptional control, alternative splicing of specific pre-mrna can generate different protein from a single gene. Evolution: evolution is a change in heritable traits of biological populations over successive generations.

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Related Questions

1 DNA sequences found in introns provide [A] amino acid sequence information.

[B] regulatory information.
[C] no known useful information.

[D] structure for the gene.
[E] alternative DNA splicing possibilities.

3. The TATA box is a(n)
[A] sequence close to the promoter region of many genes.
[B] square-shaped sequence.
[C] enhancer consensus sequence.
[D] activator sequence necessary for proper translation.
[E] None of the above

5. Regarding genes and gene expression, which of the following is not a difference between prokaryotes and eukaryotes
[A] Eukaryotic DNA does not contain a TATA box close to the initiation site as does prokaryotic DNA.

[B] In eukaryotes, RNA polymerase requires

'transcription factors'or initiation.

[C] Prokaryotic genes are often grouped together in

operons.

[D] In eukaryotes, the regulation of several genes at once requires common control elements in each of the genes.
[E] There is a diversity of eukaryotic polymerases that is reflected in the diversity of eukaryotic promoters.

10) In eukaryotic cells, a repressor

[A] is made of DNA.
[B] binds to the enhancer region to block transcription. [

C] is located both upstream and downstream from the promoter.
[D] binds to the operator to block RNA polymerase.

[E] binds to a silencer to reduce transcription rates.

Coordinated regulation of genes in eukaryotic cells [A] is the result of positioning the same regulatory sequence in front of each gene.
[B] results from all of those genes being under the control of one promoter.

[C] occurs because related genes all have the same

operons.
[D] occurs because enhancers cause DNA to bend.

In Eukaryotic transcription, what is the difference between an enhancer, a mediator, a coactivator and a trascriptional activator protein? In your answer, for each one include (a) if it's the term refers to a DNA sequence or a protein, and if it's a protein (b) if it interacts with DNA, with another protein, or with both. Also how are enhancers different from promoters in affecting gene transcription in eukaryotes? Make sure that you include in your discussion: (c) their relative position to the transcription initiation site; (d) the role of binding sites for proteins; (e) how each affects initiation and transcriptional regulation (in the latter, make a distinction between the core and the regulatory promoter

My instructor sent me this in an email to study for a final.Please help me construct the best possible answer for this as Ihave not written a satisfactory answer to the first question allsemester.

1) As you know the final does include a comprehensive componentregarding the gene and genome. (80 pts)

This first question has to be extremely detailed. For example,"A gene is a unit of inheritance. The gene carries information forit to be passed from one generation to the next. When you combine agene with the environment you are five the necessities for aphenotype. There are many gene types and elements such as the genesfor RNAs that carry information to make proteins, genes fortransfer RNAs that carry amino acids to the ribosomes, genes forribosomal RNAs that are required for structure, function andactivities of a ribosome, genes for small nuclear RNAs that make upthe spliceosome and help to splice introns, and the genes fortelomerase RNA component (TERC). A gene must also include manyparts such as introns, exons, core promoters, regulatory promoters,activators, downstream promoter enzymes (DPE), and many others.These parts of the genes as well as the different gene types mustallow for some variation in certain conditions to allow evolutionto occur. A gene must also be able to be passed on, or inheritedfrom one generation to the next." Figures and drawings are alsoappreciated by my instructor. If you could basically just throweverything you can think of within a gene or a genome at thisquestion that would be greatly appreciated.

2) You will also need to study genetic mapping, DNA as a digitalstorage device, X chromosome inactivation and synthetic biology.(35 pts)