[DEXSeq] exon counts to "PSI" (exon inclusion level)

[yerbol]

Hello all,

I`m using DEXSeq to find differential splicing. It operates with raw counts of reads aligned to the exonic segments. But frequently it is worth to have inclusion levels ("PSI") assigned to exons, which is proportion of transcripts including given exonic segment among all transcripts of given gene.

Calculation of absolute expression level of exon is seems to be not very difficult (something like FPKM): exon count * size factor (or divided to the size of library) / length of exon.

But for inclusion level we need to find ratio of expression level of exon (FPKM/counts normalized to length) to the expression level of whole gene:
something like "PSI" = "exonFpkm"/"geneFpkm".

Is there any smart way to calculate something like PSI from exon count objects used in DEXSeq?

Thank you.

[DerSeb]

Hi yerbol,

we have done just that:

http://onlinelibrary.wiley.com/doi/10.1002/0471142905.hg1116s87/abstract

There is also a script available that will calculate the PSI scores as explained in the protocol for you. You can either use count files or read files as input.

All the best,
Sebastian

[Neuromancer]

Hi Sebastian, any chance you could provide fulltext to the article you linked? Can't get it though my university....

Thanks,

Roman

[DerSeb]

Dear Roman,

feel free to contact me at:

sebastian.schaefer and at the domain nhcs.com.sg

Thanks for your interest in our work,
Sebastian