DIFFERENTIAL LOCATION OF NUCLEIC-ACIDS WITHIN INTERCHROMATIN GRANULE CLUSTERS

We have examined in great detail the distribution of nucleic acids wit hin interchromatin granule clusters in different cell types by means o f various immunocytochemical approaches. Using the in situ polyadenyla te nucleotidyl transferase-immunogold technique for RNA detection or a nti-RNA antibodies, we decisively demonstrate the presence of apprecia ble amount of RNA in clusters of interchromatin granules of untreated cells. Neither the in situ terminal deoxynucleotidyl transferase-immun ogold technique nor anti-DNA antibodies, nor the in situ nick-translat ion technique for DNA detection have revealed any DNA in the interchro matin granule clusters. However, dispersed chromatin sensitive to DNas e I are found at the borders and in the close vicinity of interchromat in granule clusters. The results indicate that interchromatin granule clusters should not be nuclear structures directly involved in RNA tra nscription but rather in some other steps of RNA metabolism.