Genome organization of prophiGD21-3 and prophiGD54-2. The organizations of prophageGD21-3 (A) and prophiGD54-2 (B) are shown, with the genes represented as boxes above and below the genome rulers indicating rightward and leftward transcription, respectively. Genes are colored according to the sequence “phamilies” they are assigned to, and tRNAs are represented as black bars. Putative gene functions are indicated above the genes. Genes 5 to 43 of prophiGD21-3 and 57 to 133 of prophiGD54-2 are predicted to be transcribed early in lytic growth, with genes 44 to 76 and 20 to 50, respectively, coding for virion structure and assembly proteins that are expressed late in lytic growth.