Biochemistry Lecture No. 37: Molecular Basis Of Cancer
Tuesday December 4 , 2012
Open Reading Frames (Cont’d):
-If an ORF is going to be expressed in protein, we are going to find mRNA for that ORF somewhere
(which is why a Northern Blot Analysis or a PCR using cDNA would be favourable). Functional ORFs also
should possess appropriate regulatory sequences such as the -10 and -35 sequences in prokaryotes (E.
Coli) and the TATA box or poly-A tail in eukaryotes. Ultimately the best test for determining if you have a
functional ORF is to actually identify the sequence with that of an existing protein’s. Remember that not
all functional genes encode proteins. The most notable exceptions are functional RNAs (e.g. tRNAs,
ribosomal genes) and these can often be recognized by the presence of related sequences in other
organisms and by their conserved secondary structure. Small regulatory RNA molecules are by far the
hardest to annotate because of their small size and the fact that they are not conserved throughout
Next Generation Sequencing:
-Next generation sequencing is the modern method of DNA sequencing that involves sequencing a
whole bunch of DNA molecules on a chip at the same time. This method is incredibly low cost and quite
rapid in processing results.
-Benign tumours are contained within the originating tissue and can be removed surgically. Malignant
tumours are able to invade surrounding tissues and are thus much more difficult to treat. Metastasis is
the process by which tumours move from the primary stage to other parts of the body. They [primary
tumours] do so by breaking through the basal lamina and into the lymphatic system or blood vessels
where they migrate to other parts of the body.
Cancer As A Genetic Disease:
-Cancer is largely a genetic disease with some epigenetic f