Physical map of the linear chromosome of Streptomyces griseus.

The chromosomal DNA of Streptomyces griseus 2247 (a derivative of strain IFO3237) was digested with several restriction endonucleases and analyzed by pulsed-field gel electrophoresis (PFGE). Digestion with AseI and DraI gave 15 and 9 fragments, respectively, the total sizes of which were 7.8 Mb. All the AseI and DraI fragments were aligned on a linear chromosome map by using linking plasmids and cosmids. PFGE analysis of the intact chromosome also showed a linear DNA band of about 8 Mb. Detailed physical maps of both terminal regions were constructed; they revealed the presence of a 24-kb terminal inverted repeat on each end. PFGE analysis with and without proteinase K treatment suggested that each end of the chromosome carries a protein molecule.