TFIP11 Interacts with mDEAH9, an RNA Helicase Involved in Spliceosome Disassembly

Yeast proteins Ntr1, Ntr2 and Prp43 function in spliceosome disassembly. An Ntr1-Ntr2 protein complex recruits Prp43 to allow the removal of the lariat-intron in late-stage RNA splicing activity. Based on amino-acid sequence similarities across species, TFIP11 and mDEAH9/Dhx15 have been identified as homologues of yeast Ntr1 and Prp43, respectively. The N-terminal region of TFIP11 contains a G-patch, which is a highly conserved domain of many RNA-processing proteins. TFIP11 displays a unique and characteristic subnuclear localization pattern, in close proximity to SC35 nuclear speckles. Transfected GFP-tagged mDEAH9 displays an evenly distributed nuclear localization and is excluded from the nucleoli; however when TFIP11 and mDEAH9 are co-transfected, both proteins colocalize to distinct nuclear speckles. These data show that TFIP11 recruits mDEAH9 suggesting that these two proteins have similar biological activities to their yeast counterparts.