Kiyoshi Mizobuchi
The E. coli Genome Group, Department of Applied Physics and Chemistry, University of Electro-Communications, Chofushi, Tokyo 182, Japan.
The project for the systematic analysis o the E. coli genome has been starting 4 years ago. The purpose of this project is to determine clockwise the nucleotide sequence from the 0 min region of the chromosome using the Kohara library. Up to the date, we have determined two contiguous 131,801 and 86,114-bp DNA sequences spanning the regions between thr at 0 min and lpd at 3.8 min and between rpsB at 4.2 min and thrW at 6.2 min, respectively. Analysis of these sequences identified 182 potential open reading frames, permitting for us to calculate the size of 1.2 kb per gene in average. This calcultion also permits to estimate about 4000 genes present in the E. coli genome. More than half the open reading frames showed similarity to other sequences. Those include, for example, a cluster of 4 genes responsible for the symbiotic nitrogen fixation or electron transport (fix ABCX) in Azorhizobium caulinodans. We also found a new class of the 120-bp repetitive sequences, RSA, which are distributed among enteric bacteria. The sequenced regions contained several RNA genes and IS elements.