CREB1 and infection: Instead, HHV-6B induced an increase in FOXO1 (2, 3 and 6 d.p.i.)and CREB1 (6 d.p.i.)expression and a down-regulation of ESR1 at 3 d.p.i. Other transcription factors displayed a biphasic modulation, as they were differently regulated by viruses at early and late time-points post-infection: the GATA family, HNF1A and HNF4A.