The N terminal region containing the serine rich ( S ) domain , the central RNA recognition motif ( RRM ) , and the C terminal arginine / serine / proline rich ( RS / P ) domain of RNPS 1 interact with p 54 , pinin , and hTra 2 beta , respectively . ^^^ Overexpression of RNPS 1 in HeLa cells induced exon skipping in a model beta globin pre mRNA and a human tra 2 beta pre mRNA . ^^^