The overall objective is to elucidate some of the mechanisms for the control and regulation of DNA-dependent RNA transcription in chloroplasts of Euglena gracilis. Specific projects include the following: (1) Location and DNA sequence analysis of chloroplast transcription units and putative regulatory regions, (2) Quantitation of changes in specific transcripts during light induced chloroplast development, (3) Characterizing in an in vitro system the components involved in selective RNA transcription. In the coming year we plan the following projects: (1) Continue DNA sequence analysis of portions of the ribosomal RNA transcription units, and selected mRNA coding regions, including the gene for the large subunit of ribulose-1,5 -bis phosphate carboxylase, (2) Complete a study of the subunit structure of chloroplast RNA polymerase, (3) Analyze the primary transcripts and processing pathways via solution and Northern hybridization analysis for some specific transcription units for which DNA sequence data are available, (4) Continue a general program of mapping, cloning, and gene localization for the Euglena chloroplast genome.