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Flashcards in Review Day Deck (14):

Why do the authors use heat to inactivate Schneider cells?

  • Heat-inactivation is done to inactivate complement, a group of proteins within cells. 
  • To destroy most heat-labile proteins prior to performing neutralizing antibody assays.
  • Proteins, such as complement, can interfere with the immune response of cell lines. 


What is a transient transfection?

  • In transient transfection, the nucleic acids introduced into the transfected cell are not permanently incorporated into the cellular genome.
  • Therefore, the effects of the nucleic acids within the cell last only a short amount of time.


Was there a selection marker on the plasmid in the paper?

Probably yes. 


Know the different vectors and what nutritional markers are used for


Difference between squelching and quenching?

  • squelching
    • When enhancer concentration is so high (saturation) that transcription is no longer increased. Rather, it decreases slightly because other cellular processes are interfered with by the high protein count. 

  • quenching
    • when the presence of a repressor near an enhancer protein interferes with normal enhancer function. 


Why would you gut the transposable element in Drosophila genomes? 

  • You gut it because and insert your own gene of interest because the gene of interest can become permanent within the genome.
  • Also, the transposable element can no longer "jump around" within the genome.


Why would the researchers perform the same experiment with trans genes in different locations?

  • This is to show if the location within the genome is a factor. (i.e. differentiate between long range and short range regulation)


What is the difference in concentrations of transcription factors in relation to the sharpness of the stripe?

  • More transcription factors => more bind sites -> sharper stripe


How does the paper relate to the lac operon?


How does the CAP function as an enhancer? Is it really an enhancer?

How does the cap function as an enhancer?

  • An enhancer is a regulatory sequence within in a bacterial operon that facilitates transcription. It interacts with RNA polymerase to promote transcription. 
  • CAP facilitates transcription by binding to the DNA and allowing normal RNA polymerase to function. 
  • CAP-> Protein, enhacner-> sequence

Is it really an enhancer?

  • Nah, it is a protein not a sequence. 


What does the insulator really refer to?

  • The actual insulator sequence
  • They bind specific proteins.
    • These proteins actually interact with each other and organize transcription
  • They are more a structural component of the genome and are not transcribed. 
  • 300-2,000 bp long
  • Sequence-specific proteins bind to them and stop transciption. 


What is a nucleosome?

  • A nucleosome is a basic unit of DNA packaging in eukaryotes, consisting of a segment of DNA wound in sequence around eight histone protein cores.
  • Nucleosomes form the fundamental repeating units of eukaryotic chromatin, which is used to pack the large eukaryotic genomes into the nucleus while still ensuring appropriate access to it.


Describe these figures

  • The orientation of the enhancer (i.e. which strand it is on) does not factor into its activity. 
  • The position of the enhancer (i.e. where it is on the plasmid) does not factor into its activity.