HOMOLOGS OF ESCHERICHIA-COLI RECJ, GLTX AND OF A PUTATIVE EARLY GENE OF AVIAN CHLAMYDIA-PSITTACI ARE LOCATED UPSTREAM OF THE LATE OMP2 LOCUS OF CHLAMYDIA-PSITTACI STRAIN GUINEA-PIG INCLUSION CONJUNCTIVITIS

The nucleotide sequence of nearly 6 kb of genomic DNA located immediat ely upstream of the omp3-omp2 operon of Chlamydia psittaci strain GPIC was obtained, revealing four significant open reading frames (ORFs), named ORF1, ORF2, ORF4 and ORF5. Searches for homologous sequences in the GenBank/EMBL databases have revealed that: (a) the open-ended ORF1 putatively encodes an homolog of RecJ of Escherichia coli, thought to be required for RecBCD-independent and conjugational recombination, a nd for UV repair; (b) the predicted translation product of ORF4 is hig hly homologous to the putative product of EUO, a previously described ORF of avian C. psittaci strain 6BC which is preferentially transcribe d early during the life cycle; and (c) ORF5 putatively encodes an homo log of bacterial glutamyl-tRNA synthetases. This analysis establishes the genetic linkage of late (omp3-omp2) and of a proposed early (EUO) genes in Chlamydia.