Updated project metadata. We hypothesized that specific proteins associate with Tnp mRNAs to suppress or stimulate their translation. We took a proteomics approach and developed a method to isolate endogenous mRNA species and their associated proteins. We employed biotinylated DNA oligonucleotides and avidin resin to capture endogenous Tnp mRNAs and associated molecules from testis extract, and we specifically eluted the complexes with non-biotinylated oligonucleotides. We then used mass spectrometry to identify proteins that were associated with the Tnp1 and Tnp2 mRNAs but not Actin mRNAs. We hypothesize that the proteins that are specifically enriched by Tnp1 and Tnp2 mRNA pulldowns relative to Actin mRNA pulldown may function to regulate these transcripts.