Analysis of the mycoplasma genome by recombinant DNA technology.

A library of DNA fragments from Mycoplasma sp. strain PG50 has been made in the vector pBR325. Analysis in Escherichia coli minicells of randomly picked clones from this library demonstrated that many plasmids can promote synthesis of mycoplasma protein in the E. coli genetic background. Screening with labeled rRNA identified plasmids with sequences from the beginning of the rRNA cistron to about two-thirds within the gene for 23S rRNA. Use of these plasmids as probes allowed an accurate determination of the number of RNA cistrons as two, and demonstrated that the cistrons are more than 20 kbp apart. The DNA sequence of 16S rRNA and the surrounding control regions has been determined.