The DNA sequence of a 1.77 kb region of the Streptomyces coelicolor chromosome containing the coding and regulatory regions of the extracellular agarase (dagA) gene was determined. The sequence predicts a primary translation product of 309 amino acids and M_r 35132. Comparison of the N-terminal sequence determined for the mature extracellular protein with that of the primary translation product deduced from the DNA sequence predicts the presence of a 30 amino acid signal peptide. Analysis of the transcription of the dagA gene using high resolution S1 mapping, in vitro transcription, dinucleotide-primed in vitro transcription and in vivo promoter probing identified four promoters, initiating transcription approximately 32, 77, 125 and 220 nucleotides upstream of the coding sequence.