BIOL 2030 Lecture Notes - Lecture 20: Hybridization Probe, Complementary Dna, David Baltimore

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3 May 2018

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Cloning Genes and mRNA Transcripts

March 14, 2016

Identification of specific DNA (gene) sequences by:

• Complementation

• Hybridization

Genome = all genetic information for an organism

• Restriction enzymes are used to cut DNA into fragments which are then spliced into a

complementary restriction site in a plasmid that contains antibiotic resistance

• Recombinant plasmids are used to transform an antibiotic sensitive strain under

conditions that ensure each bacterial cell receives no more than one plasmid

• The cells are grown on antibiotic containing solid nutrient medium; only those with

plasmid survive

Cloning by Complementation: requires a mutant strain of the bacterium or other host organism

• Host E. Coli with mutant in His-biosynthetic genes; these cells cannot synthesize

histidine and hence, cannot grow on minimal medium

• A plasmid carrying a copy of His+ biosynthetic gene is introduced to E. Coli: the cells

can now synthesize histidine and grow on a minimal medium

• Steps:

o Purify total DNA from wild type strain of E. Coli (genomic DNA w His+)

o Cleave E. Coli with restriction endonuclease

o Construct a genomic library with E. Coli DNA in a suitable cloning vector

o Transform a mutant strain that lacks ability to synthesize His

o Plate is transformed by bacterial mutant cells on minimal medium

o Colonies of cells that grow on plates are selected as they contain cloned histidine

biosynthetic gene

• Limitation: need mutant strain with complementary normal gene in biosynthetic

pathways; genes that code for structural proteins are harder to complement

Cloning by Hybridization

• Requires hybridization probe that is complementary (or partially complementary) to the

targeted cloned DNA sequence

• Bacterial colonizies are transferred to a nitrocelluloae filter

• Filter with bacteria are lysed and the DNA is denatured (using NaOH to break bonds and

bacterial cells)

• Radioactively labeled nucleic acid probe in added

• Some of the radioactive nucleic acid probe molecules become hybridized to the DNA of

some colonies

• Creates exposed x-ray film

Complexity of Eukaryotic Genome

• Intergenic region

• Introns

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Related Questions

View/perform/read ALL THREE of the following prior to answeringthe questions.

http://highered.mcgraw-hill.com/olcweb/cgi/pluginpop.cgi?it=swf::535::535::/sites/dl/free/0072437316/120078/micro10.swf::Stepsin Cloning a Gene (Links to an external site.)

http://www.discoverbiotech.com/wiki/-/wiki/Main/Applications ofCloning (Links to an external site.)

http://www.wiley.com/college/boyer/0470003790/animations/cloning/cloning.htm(Links to an external site.)

Skip to question text.

From the list below, which of the following is the most logicalsequence of steps for splicing foreign DNA into a plasmid andinserting the plasmid into a bacterium?
I. Transformbacteria with recombinant DNA molecule
II. Cutthe plasmid DNA using restriction enzymes
III. Extractplasmid DNA from bacterial cells
IV. Hydrogen-bondthe plasmid DNA to nonplasmid DNA fragments
V. Useligase to seal plasmid DNA to nonplasmid DNA

Flag this Question

Plasmids (or vectors) are important in biotechnology becausethey are

a vehicle for the insertion of recombinant DNA intobacteria.

surfaces for respiratory processes in bacteria.

recognition sites on recombinant DNA strands.

surfaces for protein synthesis in eukaryotic recombinants.

proviruses incorporated into the host DNA

Flag this Question

Plasmids are put into bacterial cells by

restriction enzymes

DNA ligase

binding of cohesive sticky ends

transformation

Flag this Question

Restriction enzymes usually

cut donor DNA evenly so smooth edges result

cut donor DNA but do not affect plasmids

make staggered cuts at specific sequences in DNA in both donorDNA and plasmid

are used in ligating plasmids into bacterial host cells

more than one of the above

Flag this Question

After combining DNA fragments in a cloning experiment, ___ isused to covalently join the DNA segments.

Restriction enzyme

DNA Ligase

Reverse transcriptase

DNA polymerase

Helicase

Flag this Question

It is theoretically possible for a gene from any organism tofunction in any other organism. Why is this possible?

All organisms have ribosomes.

All organisms have the same genetic code.

All organisms are made up of cells.

All organisms have similar nuclei.

All organisms have transfer RNA.

Flag this Question

Skip to question text.

Assume that you are trying to insert a gene into a plasmid andsomeone gives you a DNA sample cut with restriction enzyme X. Thegene you wish to insert from the given sample has sites on bothends for cutting by restriction enzyme Y. You have a plasmid with asingle site for Y, but not for X. Your strategy should be to

cut the plasmid with restriction enzyme X and insert thefragments cut with Y into the plasmid.

cut the plasmid with enzyme X and then insert the gene into theplasmid.

cut the DNA again with restriction enzyme Y and insert thesefragments into the plasmid cut with the same enzyme.

cut the plasmid twice with restriction enzyme Y and ligate thetwo fragments onto the ends of the human DNA fragments cut withrestriction enzyme X.

insert the fragments cut with X directly into the plasmidwithout cutting the plasmid.

Flag this Question

Which of the following is/are false in regard to expressionplasmids (also called expression vectors)?

They are used to make proteins using a cloned gene.

They contain a promotor.

They are the first plasmid type used to clone a gene.

They contain a terminator.

More than one of the above is false.

Flag this Question

What is NOT a potential problem(s) associated with usingbacteria containing a cloned eukaryotic gene (e.g. a human gene) toproduce a functional protein?

If the eukaryotic gene contains introns the bacteria will notremove them and the resulting amino acid sequence will be differentthat that made by a eukaryote.

The bacteria may not fold the protein correctly.

The bacteria may degrade the protein.

All of the above are potential problems.

Flag this Question

Cloning allows for production of proteins in much larger amountsthan occurs in the cells from which the gene is isolated.

True

False

Flag this Question

Question 111 pts

Gene cloning is used to do all of the following except

Make insulin

Making genetically identical animals (e.g. Dolly thesheep)

Make vaccines

Perform Gene Therapy

Making genetically engineered plants

Flag this Question

In your

rubyhedgehog47

What would you use to join two DNA fragments to each other?

Select one:

a. Restriction enzyme

b. Ligase

c. Chaperonin

d. Plasmid

The activity of pyruvate kinase is controlled by which of the below agents

Select one or more:

a. Fructose-6-phosphate

b. Fructose-1,6-bisphosphate

c. Protein Kinase A

Why do plasmids used to carry foreign genes into E. coli cells invariably also carry the gene for resistance to an antibiotic?

Select one or more:

a. The gene is required for cellular replication

b. The gene is necessary for the lac operon system to operate

c. The gene is necessary to safely grow the bacterium in the laboratory without risk of containment breach

d. To enable selection for only those cells that carry the plasmid with the foreign gene of interest

View/perform/read ALL THREE of the following prior to answeringthe questions.

http://highered.mcgraw-hill.com/olcweb/cgi/pluginpop.cgi?it=swf::535::535::/sites/dl/free/0072437316/120078/micro10.swf::Stepsin Cloning a Gene (Links to an external site.)

http://www.discoverbiotech.com/wiki/-/wiki/Main/Applications ofCloning (Links to an external site.)

http://www.wiley.com/college/boyer/0470003790/animations/cloning/cloning.htm(Links to an external site.)

Skip to question text.

Flag this Question

Plasmids (or vectors) are important in biotechnology becausethey are

a vehicle for the insertion ofrecombinant DNA into bacteria.

surfaces for respiratoryprocesses in bacteria.

recognition sites onrecombinant DNA strands.

surfaces for protein synthesisin eukaryotic recombinants.

proviruses incorporated intothe host DNA

Flag this Question

Plasmids are put into bacterial cells by

restriction enzymes

DNA ligase

binding of cohesive stickyends

transformation

Flag this Question

Restriction enzymes usually

cut donor DNA evenly so smoothedges result

cut donor DNA but do notaffect plasmids

make staggered cuts atspecific sequences in DNA in both donor DNA and plasmid

are used in ligating plasmidsinto bacterial host cells

more than one of theabove

Flag this Question

After combining DNA fragments in a cloning experiment, ___ isused to covalently join the DNA segments.

Restriction enzyme

DNA Ligase

Reverse transcriptase

DNA polymerase

Helicase

Flag this Question

It is theoretically possible for a gene from any organism tofunction in any other organism. Why is this possible?

All organisms haveribosomes.

All organisms have the samegenetic code.

All organisms are made up ofcells.

All organisms have similarnuclei.

All organisms have transferRNA.

Flag this Question

Skip to question text.

cut the plasmid withrestriction enzyme X and insert the fragments cut with Y into theplasmid.

cut the plasmid with enzyme Xand then insert the gene into the plasmid.

cut the DNA again withrestriction enzyme Y and insert these fragments into the plasmidcut with the same enzyme.

cut the plasmid twice withrestriction enzyme Y and ligate the two fragments onto the ends ofthe human DNA fragments cut with restriction enzyme X.

insert the fragments cut withX directly into the plasmid without cutting the plasmid.

Flag this Question

Which of the following is/are false in regard to expressionplasmids (also called expression vectors)?

They are used to make proteinsusing a cloned gene.

They contain a promotor.

They are the first plasmidtype used to clone a gene.

They contain aterminator.

More than one of the above isfalse.

Flag this Question

What is NOT a potential problem(s) associated with usingbacteria containing a cloned eukaryotic gene (e.g. a human gene) toproduce a functional protein?

If the eukaryotic genecontains introns the bacteria will not remove them and theresulting amino acid sequence will be different that that made by aeukaryote.

The bacteria may not fold theprotein correctly.

The bacteria may degrade theprotein.

All of the above are potentialproblems.

Flag this Question

Cloning allows for production of proteins in much larger amountsthan occurs in the cells from which the gene is isolated.

True

False

Flag this Question

Question 111 pts

Gene cloning is used to do all of the following except

Make insulin