hi,
I'm sorry I do not have any experience in interpreting circRNAs. The identification using sequences was a generic step hence replied initially. Having said that there are a few low hanging fruits you could go for if you haven't already -
- Use BLAST E-value to select high-confidence candidates. (if you have too many to strt with)
- Assuming you are working with human/ mouse, ENCODE is a wonderful resource to test hypothesis. For your high-confidence candidates, go to the UCSC browser, turn on ENCODE tracks and see if you have sign of promoter upstream (like histone marks, TFBS etc.).
- Also you could check if the region has transcription signal in other ENCODE datasets as well