sentence: Thus , the mostly cytoplasmic ( LTV1 , RIO2 , NOB1 ) and early nucleolar RBFs ( TBL3 , FBL , PES1 ) are preferentially detected in the supernatants obtained after the first ( SN1 ) and the third ( SN3 ) fractionation steps of the PSE method , respectively ( Fig. 1b , lanes 4 – 6 ) .