Genetic Biotechnology Terms

CRISPR-Cas9

CRISPR-Cas9

• Includes the cas9 nuclease & the guide RNA

• The guide RNA binds to the target sequence, which acts as a guide to the cas9, which cleaves the sequence

• The sequence can then be edited using cell DNA machinery to add or delete sequences, or by designing a new sequence to add to the sequence.

• The two ends are then repaired by using 1 of the 2 repair sequences:

  • Nonhomologous end joining (NHEJ) → brings broken DNA ends together; more faster and frequently used. 

  • Homology directed repair (HDR) → uses a homologous DNA template to repair the break. Less error prone. 

Gene Therapy

• Provides healthy & normal gene copies to replace the mutated ones.

• Uses viral vectors → viruses that are modified to include the therapied gene and not the harmful virus genome. 

  • Enters target cells and releases the therapies gene in there.

Gene Switching

• Regulatory DNA sequences that can turn gene expression on and off. 

• Regulatory proteins bind to these sequences in order to turn on and off genes.

•  Non Coding sequences.

Exon Skipping

• Removes the mutation from the RNA by changing how the primary transcript in an RNA sequence is spliced. 

• Antisense RNA binds to the part of the RNA transcript that has the mutation, causing the splicing machinery to skip over segments of the sequence that includes the mutation.

RNA Interference

• Involves small RNA segments that target sequences for destruction.

• Small interfering RNA is the most commonly used.

  • siRNA is cleaved and incorporated into cellular protein complexes which then cleave the mRNA sequences

• Artificially shuts down gene expression.

Small Molecule Drug

• Synthesized low weight chemical compounds that are taken up by cells.

• Can restore mutated proteins back to normal or block the negative effects of mutated proteins.