I spent some time looking for the PRNP and trying to understand its mysteries. Even though PrP is 209 amino acids (253 pre-translation, which is what the codon numberings are based on), the PRNP gene clocks in at 15.36 kb. So when I first saw it, I wondered, what IS all that other stuff? Ensembl’s gene summary with its list of five “transcripts” didn’t help me that much. There are two 253-aa protein coding sequences listed, which both point to the same link, which I looked at a bit. It looks mostly right as a reference sequence– 127G, 178D, 219E– although it’s a bit weird in that it lists codon 129 as Y (Tyrosine), not a genotype I’ve ever heard of.
NCBI’s page on PRNP was a bit more helpful — it actually lists the different components of the PRNP gene with a bit of description of each. If you scroll down to CDS, that appears to be the one of interest since it is described as:
prion-related protein; major prion protein; CD230 antigen; prion protein PrP; prion protein (p27-30) (Creutzfeldt-Jakob disease, Gerstmann-Strausler-Scheinker syndrome, fatal familial insomnia)
And if you click the CDS link, it highlights the DNA sequence that generates PrP.
Question: so what are the other 15.36 kb? Is any of that other stuff transcribed or translated? Is there any alternative splicing or is PrP the one and only product of PRNP?