STRUCTURAL ORGANIZATION OF THE PRE-MESSENGER-RNA SPLICING COMMITMENT - A HYPOTHESIS

Several models have been presented in the past to explain localized di stributions of nuclear RNAs from individual genes that range from smal l foci to more elongated ''track-like'' structures. We present here a hypothesis which explains that, in the case of regulated splicing, the re is in diploid cells a spatial separation of transcription sites fro m the execution of regulated splicing which we situate to domains of S R protein accumulation, In addition, it explains the presence of poly( A) sequences, and the lack of the autoradiographic label due to short pulses of [H-3]uridine, in these domains. (C) 1996 Academic Press