Lesson 1 CRISPR 241008

Crispr Course - SoundBio - 08-10-24

Cemtral Dogma (molecular biology): DNA -> Transcription -> RNA ---------> Protein info storer Messenger Carry out cell Functions

DNA replicated from DNA polymerase

DNA Strip - Helix - Nucleotides - 4 different nucleotides - G C A T - G pairs w/ C - A pairs w/ T - G/A called purines - C/T called pyrimidines

backbone - 5', 3' on the backbone - filled with sugar and phosphate - phosphate attacked to the 5' end of the sugar-pentagon molecule - count starts from the hydroxal group

Transcription - Protein comes in and makes a inverse strand (RNA polymerase) || 'ase - means its an enzyme - RNA formed: 5' ... AGCUUC ... 3' - U replaces the T in strand - change molecule by something like a hydrogen add on

Translation - Ribosome (protein) - The rna fed through the ribosome - 3 base pair - tells ribosome of what type of amino acid - 16 base pairs - AGC, UUC - N ... S -- Ph ... C

Virus - Outside has: spike protein - Human cell: Ace2 - Attaches Ace2 <-> Spike Protein - injects genome into the human cell

Crispr History

  • 1987 - looking at ecoli

    • ecoli - common bacteria, (eg: k22 variant ecoli strain)
    • chipotle - pathogenic ecoli
    • found repeating segments every stretch and spacer sequences
    • spacer sequences - clustered regularly interspaced palandoming repeats
    • AATGGCAT
    • called "hairpins" - palindomes

  • 1993

    • More CRISPR was found
    • People were lining up CRISPR sequences
    • Noticed some nucleotides changed over species thinking this might be a gene change evolutions

  • Early 2000s

    • looking at spacer sequences
    • has homologous spacer sequences in viruses
    • if the bacteria had a spacer sequences the same as the virus, it won't be infected

  • 2007

    • Yogurt company - Danisco
    • bacterial strain for culturing yogurt would get infected by bacteria phages
    • strepicocus thermophilic bacteria used to make yogurt
    • inserted a part of the bacteria phage into the yogurt bacteria
      • replace the spacer of the yogurt bacteria with virus
    • worked! no infections!
    • tased same/ same output

  • 2008

    • the spacer sequences were transcribed into RNA
    • CAS - crispr associated genes - the sequence after the crispr sequence
    • CAS9 - can introduce double standed breaks into DNA (can cut a whole piece of dna rather half like Nickase, "nicks" dna, cuts half)
    • transactivating rna
    • guide rna tells where the cas9 should cut the DNA
    • tracRNA - segment of CAS
    • tracRNA + crRNA (segment of CRISPR) -> sgRNA (guide RNA)
    • we can: deactivate CAS0 -> dcas9
    • we decativate by creating 2 mutations dcas9 (in the cutting regions)
    • dCAS9 - we can add cool things to it (enzymes/proteins)
    • you can either add a new segment to a cut of a gene or kill a dna sequence by using a CAS9 double helix cut

  • 1997 - Gattaca Released