passages.id: split_4_test_968_passage
passages.type: progene_text
passages.text: Therefore , we decided to use the HX1 region to ameliorate the performance of the cryptic trans - splicing signal present in the T. cruzi expression vector pRIBOTEX ( Martinez - Calvillo , S. , LÃ?Â³pez , I. , Hernandez , H. , 1997. pRIBOTEX expression vector : a pTEX derivative for a rapid selection of Trypanosoma cruzi transfectants. Gene 199 , 71-76 ) .