This award provides interim funding for a project aimed at elucidating the mechanism of control of the events involved in pre-mRNA processing. Specifically, ultrastructural methodology will be used to visualize spliced some formation in vivo on nascent transcripts. The project was started under NSF support. It will be funded fully by NIH later this year. The award will enable the principal investigator, who is currently without funding, to continue her research without disruption while she is between grants.