Hd1 Rabbit pAb (A20268)

Probable transcription factor involved in the regulation of flower development. Required for the promotion of flowering under short day (SD) conditions and the suppression of flowering under long day (LD) conditions. Regulates positively the floral activator HEADING DATE 3a (HD3A) under SD and negatively under LD conditions. The GIGANTEA-CONSTANS-FLOWER LOCUS T (GI-CO-FT) pathway to control photoperiodic flowering under LD is conserved between Arabidopsis and rice, but the regulation of the downstream gene by the upstream regulatory gene is reversed in the two species. In Arabidopsis, GI acts as an activator of CO, which in turn activates the floral activator FT under LD conditions. In rice, GI activates HD1/CO in a similar manner to that in Arabidopsis. However, under LD conditions, HD1 suppresses HD3A/FT expression, causing the suppression of flowering.