🏷️ LIMITED TIME OFFER: GET 20% OFF GRADE+ YEARLY SUBSCRIPTION →
Log in
HomeClass Notes1,200,000CA670,000

BIOL 1020 Lecture Notes - Lecture 5: Agarose Gel Electrophoresis, Northern Blot, Reverse Transcriptase

27 views2 pages
mauvesnake886
25 Nov 2014
School
University of Guelph
Department
Biology
Course
BIOL 1020
Professor
Dan

For unlimited access to Class Notes, a Class+ subscription is required.

Document Summary

Detection of gene expression and foreign dna integration. The end product of translation would be protein. First two methods are detection of gene expression at mrna level (rt pcr and northern. Western blotting detection of gene expression at the protein level. Southern blotting- detection of foreign gene integration into the genome. Rt pcr- its purpose is to detect mrna level, so we want to reverse transcribe mrna to make cdna. Step one is to use reverse transcriptase from the rna virus. After we make cdna we have double strand (1 rna 1 cdna) thick and thin bands represent high expression vs low expression. Step 1 isolate rna first then separate it based on the size through gel electrophoresis. After you do this, it is difficult to do a detection on the agarose gel because it is very thick. Thus, you will want to transfer the rna to a membrane making it easier to detect them.

Get access

Grade+20% off
$8 USD/m$10 USD/m
Billed $96 USD annually
Grade+
Homework Help
Study Guides
Textbook Solutions
Class Notes
Textbook Notes
Booster Class
40 Verified Answers
Class+
$8 USD/m
Billed $96 USD annually
Class+
Homework Help
Study Guides
Textbook Solutions
Class Notes
Textbook Notes
Booster Class
30 Verified Answers

Related Documents

BIOL 039 Lecture Notes - Lecture 30: Edwin Southern, Nylon, Tubulin
pucemallard867
MCB 2050 Lecture Notes - Lecture 23: Southern Blot, Northern Blot, Dna Microarray
tealarmadillo260
Biochemistry 2280A Lecture Notes - Ribonuclease H, Ecori, Sticky And Blunt Ends
beigereindeer807

Related Questions

A student written question: New Belgium Brewery creates its own yeast strains for brewing beer. Some yeast strains secret a toxic protein, which is not detectable until after the brewing process. Therefore the brewery must find a way to detect the yeast that secretes this toxic protein. Because they collaborate with Dr. Wolkow, a yeast-whiz, the brewery decides to hire you to work with Dr. Wolkow to make a cDNA expression library from the toxin-secreting strain. You decide to use a bacterial expression vector since it is easy to work with.

1. What components must the expression vector contain?

a. promoter, translation start sequence, cloned cDNA sequence, DNA polymerase

b. DNA ligase, translation start signal, cloned cDNA sequence, polyA tail

c. Shine-Dalgarno sequence, promoter, cloned cDNA sequence, antibody

d. promoter, Shine-Dalgarno sequence, cloned cDNA sequence, transcription termination sequence

2. Suppose the radioactive 3 antibody did not attach to any of the protein products. What can you conclude from this?

a. the toxic protein product is produced by all the yeast strains

b. the toxic protein product is produced by one or more of the yeast strains

c. the toxic protein product is not produced by any of the yeast

d. the yeast DNA was destroyed when the cells were lysed

3. Why would the brewer want to specifically use an expression vector rather than another type of vector?

a. It is specifically for eukaryotic DNA

b. It is used to produce the protein encoded by a cloned gene

c. It is only used for cloning cDNA sequences

d. They want to produce mRNA encoded by a cloned gene

4. This type of blot, where protein is transferred onto the membrane and is then hybridized to a tagged-antibody is a blot.

a. Southern

b. Northern

c. western

d. southwestern

Which of the following did Erwin Chargaff observe?

A)

Base composition changes as the organism ages.

B)

Base composition of DNA does not vary from one species toanother.

C)

In all species the number of adenines equals the number ofguanines.

D)

In all species A + T = G + C.

E)

DNAs isolated from different tissues of the same species havethe same base composition.

The melting temperature (Tm) of a DNA duplex is:

A)

the temperature at which double-stranded nucleic acids degradeinto free nucleotides.

B)

the temperature at which double-stranded DNA is toosingle-stranded to ever renature back to double strands.

C)

the temperature at which double-stranded DNA is completelymelted.

D)

the temperature at which double-stranded DNA has become 50%single-stranded.

E)

the temperature at which double-stranded DNA begins to melt.

Given your knowledge and the descriptions of each of thesemethods, which of the following does NOT rely on the ability ofnucleic acids to hybridize with each other?

A)

Southern blotting for the detection of specific DNA fragmentsthat have been separated by gel electrophoresis.

B)

Colony blot hybridization to identify a specific sequence from acollection of sequences that have been inserted into bacteria.

C)

Northern blotting for the detection of specific RNA fragmentsthat have been separated by gel electrophoresis.

D)

A DNA oligonucleotide microarray incubated with probes made fromcDNA.

E)

Western blotting for the detection of specific proteins thathave been separated by gel electrophoresis.

Which of the following is a possible reason why DNA uses thymineinstead of uracil?

A)

Cytidine is deaminated to uracil so it would be difficult forany repair mechanism to differentiate between uracil that belongsin the sequence and uracil that resulted from deamination.

B)

Adenine is deaminated to uracil so it would be difficult for anyrepair mechanism to differentiate between uracil that belongs inthe sequence and uracil that resulted from deamination.

C)

When uracil is bound to a deoxyribose it will become morereactive, forming covalent bonds with other bases.

D)

None of the above.

Which of the following is an enzyme used in cloning to breakcovalent bonds?

A)

DNA ligase

B)

Restriction endonuclease

C)

Reverse transcriptase

D)

DNA polymerase I

E)

Alkaline phosphatase

Which of the following could you use to remove the 5' phosphatesafter cleavage of a plasmid with a single type of restrictionenzyme to ensure that the plasmid would not simply fuse backtogether upon addition of ligase?

A)

Reverse transcriptase

B)

Alkaline phosphatase

C)

DNA ligase

D)

DNA polymerase I

E)

Restriction endonuclease

Which of the following would you use to create a cDNA librarythat you would not use for a genomic library?

A)

Alkaline phosphatase

B)

Reverse transcriptase

C)

Restriction endonuclease

D)

DNA ligase

E)

DNA polymerase I

A plasmid vector typically has which of the followingfeatures?

A)

An origin of replication

B)

A selectable marker to ensure that the only bacteria growingcontain the intact or recombinant vector.

C)

Unique restriction sites for insertion of DNA.

D)

Small size to facilitate entry into the cell and biochemicalmanipulation of the DNA.

E)

All of the above are features of plasmid vectors.

Which of the following is FALSE of genomic or cDNAlibraries?

A)

Genes represented in cDNA libraries include control sequencesthat direct transcription.

B)

cDNA libraries contain cDNAs made from mRNA.

C)

Genomic libraries contain fragments of genomic DNA that aregenerated by partial digests with restriction enzymes.

D)

Genomic libraries usually contain large fragments and are likelyto be constructed in YAC or BAC vectors.

E)

cDNA libraries contain sequences from expressed genes only.

Which of the following is NOT a typical component of apolymerase chain reaction (PCR)?

A)

dNTPs

B)

DNA containing the sequences to be amplified

C)

DNA ligase to connect the fragments together

D)

Primers complementary to each end of the sequence to beamplified

E)

Heat stable Taq polymerase

How can a fusion protein be formed?

A)

Site-directed mutagenesis where a fragment is replaced with asynthetic sequence containing the altered DNA sequence.

B)

Two proteins can recombine in the bacterial cell to form a newhybrid protein.

C)

Portions of two different genes are ligated together to create anew hybrid gene. When expressed the gene product is a fusion of thetwo gene products.

D)

Using oligonucleotide-directed mutagenesis to introduce specificmutations that cause the expressed protein to fuse to otherproteins.

E)

A portion of the gene can be removed to form a shorter gene andtherefore a shorter protein.

Why is green fluorescent protein (GFP) so useful in visualizingfusion proteins in eukaryotes?

A)

The GFP protein recognizes and binds to fusion proteins allowingthe location of the fusion protein to be determined.

B)

The reaction is only dependent on the presence of GFP and oneother cofactor.

C)

It is easily cloned and expressed in bacterial cells.

D)

The presence of just a few molecules of GFP fusion proteins canbe sufficient for observing the proteins microscopically allowingthe study of its location and movements in the cell.

E)

It is derived from fire flies, which are easy to cultivate inthe lab.

You wish to determine the cellular location of a protein butunfortunately it is not particularly antigenic (can t develop astrong antibody response). How could you solve this problem?

A)

Create a fusion protein with an epitope tag that can bevisualized by incubation with fluorescently tagged antibody to theepitope.

B)

Create a fusion with green fluorescent protein (GFP).

C)

Express the protein as a fusion with biotin. The addition of GFPwill cause fluorescence.

D)

A and B might work.

E)

A, B, and C might work.

F)

None of the above will work.

A positive result for the yeast two-hybrid analysis means thefollowing:

A)

The proteins that you are studying can be made into fusionproteins, but do NOT interact with each other within the nucleus ofyeast.

B)

A fusion protein containing the Gal4p activation domain, hasbound to RNA polymerase resulting increase transcription ofnumerous genes, including the reporter gene, and formation ofcolonies.

C)

Two fusion proteins, one containing the Gal4p binding sitedomain and one containing the Gal4p activation domain, haveinteracted through their Gal4p domains resulting in transcriptionof the reporter gene.

D)

Two fusion proteins interact with each other and because of theGal4p binding site domain and the Gal4p activation domain containedin each fusion protein, the reporter genes are activated and thecells die resulting in no colonies.

E)

The colonies growing are expressing the two fusion proteins, butthe two proteins have not interacted with each other.

Which of the following is the approximate size of the humangenome?

A)

3 Gm

B)

300 Kb

C)

3 Mb

D)

3 Gb

E)

3 Mm

Which of the following is correct about the structure orlocation of genes?

Question 22 options:

A)

Prokaryotic genes typically possess their own regulatorysequences that only control expression of a single gene.

B)

Eukaryotic genes often encode introns that are spliced outbefore translation.

C)

Eukaryotic genes are mostly located at the telomeres and thecentromeres of chromosomes.

D)

Eukaryotic genes are typically arranged in operons.

E)

Prokaryotic genes often encode exons that are spliced out beforetranslation

After your frustration with tissue culture, you finally get your cells passaged and decide to set up your cDNA synthesis reaction, PCR, and agarose gel. You have extracted RNA from your cells, and now you need to proceed with the cDNA synthesis.

The first step is to determine the concentration of your RNA. You dilute your RNA 1:250, vortex it, move it to the cuvette, and run it on the spectrophotometer. The spec tells you that your concentration of RNA is 22µg/mL with an A260 of 0.32 and an A280 of 0.2. What is your ACTUAL RNA concentration, and what is its purity?

After determining your actual concentration of RNA, you are ready to make your cDNA. The protocol calls for the following for a total of 20µL:

5x iScript Reaction Mix – 4µL

iScript reverse transcriptase – 1µL

Nuclease free water – x µL

RNA template (100fg to 1ug total RNA) – x µL

You decide to use 500ng (or 0.5µg) of RNA in this reaction. How many µL of your RNA do you need, and how much water will you put in the tube?

You make the cDNA and get ready to set up your PCR for CD-10. The Qiagen protocol is as follows to a total of 50µL:

cDNA – 2µL

MgCl (25mM) – 4µL

CD-10 Forward Primer (10nM) – 1µL

CD-10 Reverse Primer (10nM) – 1µL

10x Buffer – 5µL

Q Solution – 10µL

dNTPs (25mM) – 2µL

Taq Polymerase – 0.5µL

Water – to 50µL

You have 2 samples plus a negative control that you need to test. How will you set up a master mix to make your pipetting more accurate and setting up this experiment go much faster than pipetting each individual component into 3 separate tubes? Remember to give yourself room for error.

While your PCR is running, you decide to go ahead and make your agarose gel. Your product size is expected to be 536bp. What percentage agarose gel do you need? How much agarose, and how much 1X TBE buffer to you need to accomplish this?

You pour your gel successfully, but use the last of the 1X TBE. You need more TBE to run the gel, but all we have is 50X TBE. You decide to make 3L of 1X TBE from the 50X TBE so that there is plenty for others (remembering your frustration from tissue culture and no PBS earlier in the day). How much 50X TBE do you need, and how much water do you need to make 3L?

Making Solutions:

You need 100mLs of a 5M solution of CaCl2. The MW of CaCl2 is 111 grams/mol. How many grams of CaCl2 do you need?

You want 25mLs of the following solution: 0.5M CaCl2 and 1M MgSO4. You have 5M CaCl2 and 2.5M MgSO4. How much of each do you add to make your final solution?

Many times, you will be using someone else’s lab notebook to formulate your own protocols. You will notice in some lab notebooks that the author will refer to nearly everything in volume rather than concentration. For example, it may say, “add 5μL DNA to the PCR tube” instead of “add 500ng DNA to the PCR tube.” Which is more accurate? Why?