a class of nonmigrating low molecular weight nuclear rna 's is associated with the structureless region of the nucleoplasm but not with the nucleoli , nuclear helices , or chromatin thus , the role of these rna 's in genetic regulation is questionable a class of migrating rna 's ( presumed , but not directly shown , to be low molecular weight ) that shuttles between nucleus and cytoplasm is also not associated with nucleoli or helices but some radioactivity is associated with the chromatin it may be , therefore , that the shuttling rna 's are in some way involved in genetic transcription or replication .
C0035709
low molecular weight nuclear rna 's
C0007610
nucleus