Functional Spliceosome Associated Protein 24 (fSAP24)

By yeast 2-hybrid screening of a HeLa cell cDNA library using human NIF3L1 as bait, followed by database analysis, Tascou et al. (2003) cloned human THOC7, which they called NIF3L1BP1. The deduced 204-amino acid protein has a calculated molecular mass of 23.7 kD and contains a predicted leucine zipper domain. THOC7 shares 97% amino acid homology to the corresponding mouse sequence. Northern blot analysis of mouse tissues detected ubiquitous Thoc7 expression. Immunofluorescence studies localized THOC7 to the cytoplasm and nucleus; however, THOC7 colocalized with NIF3L1 in the cytoplasm only. Yeast 2-hybrid analysis with THOC7 deletion mutants showed that the C-terminal leucine zipper domain was required for binding to NIF3L1.