a young scientists interested in
studying the effect of not producing or
producing very little protein from gene
a gene a is linked to a heart condition
causing the heart wall to thin the
scientists problem is that he's unable
to find cells with a mutated gene a the
scientist is looking at two approaches
RNA interference and CRISPR the goal is
to use one of these methods to reduce or
eliminate the expression of gene a RNA
interference can happen in two different
ways I can use micro RNA or small
interfering RNA the micro RNA process
starts with transcription of inverted
repeat and DNA this produces a primary
micro RNA the primary micron is cleaved
to produce RNA with a hairpin - your
access scissors and cuts the hairpin
removing his terminal loop one stranded
that micro RNA combines with the protein
organ on forming an RNA induced
silencing complex this complex binds
with mRNA  resulting in imperfect
base pairing inhibiting translation
small interfering RNA process starts off
with a double stranded RNA from an RNA
virus or a long hairpin - our access
scissors cutting the double-stranded RNA
into little pieces producing small
interfering RNAs the small interfering
RNA is combined with a protein forming
an RNA induced silencing complex this
complex pairs with mRNA forming a
perfect base pairing leading to a more
an integration a different approach
would be CRISPR CRISPR is a natural
system used by bacteria to protect
themselves from viruses when viral DNA
is detected the bacteria will produce a
matching RNA notice guide RNA guide RNA
and a protein will form a complex known
as cas9 diet RNA recognizes the
sequence that needs to be edited in this
case of ours and it leads the cas9 to
the targeted DNA. Cas9 is cutting
enzyme  that cut the target DNA. Using CRISPR
scientists can engineer any DNA at the
precise location by making it matching
guide RNA the scientists could use
CRISPR to make a guide RNA to match the
heart gene he would then add guide RNA and
cas9 to a solution to inject into a
patient who has the heart gene of
interest. the guide RNA will lead cas9
to the target DNA  where cas9 will make the
cut. the scientists can make a healthy
DNA sequence to insert into the patient
where the cut was made. the scientist
reflects back on the two methods. RNA
interference directs gene silencing
ultimately reducing gene expression
CRISPR cuts and edits DNA physically
altering it. the scientists ultimately
chose RNAi as this method silences
the gene reducing this expression. this
is exactly what he wants so he can
research the heart gene even though he
could edit the DNA using CRISPR it's
risky as cuts are error-prone and
could result in an  unwanted mutation. a mutation
could change in the hearts original gene
expression resulting in inaccurate data.
