The transcription and mRNA degradation pattern of a cloned Desulfovibrio vulgaris (Dv) Hildenborough cytochrome c3-encoding gene (cyc) was analyzed in detail, both in Escherichia coli and its native species. Transcription in Dv seems to be controlled by the same promoter elements as in E. coli; the transcription start point (tsp) of this Dv gene has been mapped in both species and found to be identical. A major putative transcription terminator was mapped and it was found to be the same in both organisms. Furthermore, the intermediates in cyc mRNA degradation are similar in both bacterial species.