. "At the beginning of this reaction, 1 molecule of 'Processive elongation complex' is present. At the end of this reaction, 1 molecule of 'DSIF complex', 1 molecule of 'FACT complex', 1 molecule of 'RNA Polymerase II holoenzyme complex (hyperphosphorylated)', 1 molecule of 'damaged DNA substrate:nascent mRNA hybrid', 1 molecule of 'Elongin Complex', 1 molecule of 'FCP1P protein', 1 molecule of 'P-TEFb complex', 1 molecule of 'NELF complex', 1 molecule of 'RNA polymerase II elongation factor ELL', 1 molecule of 'NTP', 1 molecule of 'TFIIS protein', and 1 molecule of 'TFIIF' are present.

This reaction takes place in the 'nucleus'.
"^^ . . . . . "Elongating transcript encounters a lesion in the template"^^ . . . . . . . . . . . . . .