TRANSCRIPTION OF THE ARCHAEAL TRKA HOMOLOG IN METHANOSARCINA-MAZEI S-6

Transcription of the archaeal trkA gene homolog in Methanosarcina maze i S-6 was studied at the optimal growth temperature of 37 degrees C an d after heat shock at 45 degrees C. Northern CRNA) blotting results (t ranscript size) and data from primer extension experiments to map the transcription initiation site indicate that trkA is cotranscribed with another gene. The latter, orf11, encodes a protein of 94 amino acids (10,611 Dal and is located upstream of trkA, with which it overlaps: t he translation stop codon of orf11, TGA, shares the bases T and G with the translation start codon of trkA, ATG. These genes' transcription was decreased by heat shock to the point of making the transcript unde tectable by Northern or dot blotting procedures. orf11 and trkA differ in codon usage patterns, and the proteins coded by them, i.e., Orf11 and TrkA, are dissimilar in amino acid sequence and composition.