Spliced leader trans-splicing is an essential RNA processing step that is required for the formation of mRNA in many eukaryotes, including C. elegans. However, the factors involved in this reaction are not well known. Here we perform a molecular analysis of key components in this reaction by immunoprecipitation of GFP-tagged SNA-1 and SNA-3 proteins from C. elegans embryonic extracts treated with/without RNAseA/T1 followed by the identification of associated proteins using LC-MS/MS and label-free quantification. As control, embryonic extract from wild type N2 animals were also subjected to the same treatment. Note file names (e.g. PE906_SNA1_RNase_IP_anti-GFP_beads) indicate the name of the C. elegans line (PE906_), the name of the protein tagged with GFP (SNA1) and whether samples were treated with RNases A and T1 (RNase), and for raw files whether immunoprecipitation was done with anti-GFP nanobody coupled agarose beads (IP_anti_GFP_beads), or control agarose beads (IP_control_beads), respectively. Note that SNA-3 protein is only identified by its Uniprot identifier Q9GYR5.