Biochemistry 2280A Lecture Notes - Radiography, Polyadenylation, Metastasis

• School: Western University
• Department: Biochemistry
• Course: Biochemistry 2280A
• Professor: Mel Usselman

Document Summary

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 different species.