PARN immunoprecipitates with CPSF6, in NCI-H520 Cells

The previous results suggest that PARN is involved in the early steps of miR-29a maturation. To identify factors that associate with and could recruit PARN to polyadenylated pri-miR-29a transcripts, we performed immunoprecipitation experiments in extracts of NCI-H520 cells with PARN antibody, followed by mass spectrometry. Of the identified proteins, we focused on cleavage and polyadenylation specificity factor 6 (CPSF6), the 68 kDa larger component of the mammalian cleavage factor I (CFIm), which is essential for the early steps of mRNA 3 ́ end processing and the selection of multiple poly(A) sites