rnas produced by all three polymerases (pol i, ii, iii) act as substrates for tramp complex. tramp complex is involved in processing and surveillance of various rnas and degrade abnormal rnas. different type of rna substrates include ribosomal rnas (rrnas), small nucleolar rnas (snornas), transfer rnas (trnas), small nuclear rnas(snrnas), long transcripts of rna polymerase ii (pol ii) etc. but the mechanism by which tramp complex identifies various substrates is unknown.