AtACINUS protein is involved in regulation of alternative transcription and splicing(AS). Identifying interaction partners and protein complex compositions for AtACINUS can produce valuable information on the mechanisms by which they regulate transcription and AS, as well as post-translational modifications on AtACINUS. A homozygous 35S::AtACINUS-GFP/acinus-2 plant was selected for similar protein expression level to the endogenous AtACINUS protein of wild-type plants using a native α-AtACINUS antibody. We isolated putative AtACINUS interaction partners from young Arabidopsis seedlings using the native α-AtACINUS antibody. Plants expressing TAP-GFP under 35S promoter were used as controls.