HAP3 — Oryza sativa Japonica

Summary

Os05g0463800 (HAP3, also known as NF-YB1) encodes a DNA-binding transcription factor with RNA polymerase II-specific activity, belonging to the NF-YB/HAP3 family characterized by a histone-fold domain. In rice, this gene is associated with endosperm cellularization and development, phloem loading, sucrose transport, and positive regulation of protein metabolism. It is linked to grain quality, grain plumpness, grain size, grain shape, grain density, amylose content, starch content, protein content, and grain yield per plant. Additional associations include photoperiod-sensitive flowering time, days to heading, spikelet fertility, rolled leaf, leaf chlorosis, cold tolerance, photosynthetic rate, and stomatal complex patterning and development. The encoded protein localizes to the nucleus, cytoplasm, nucleolus, plastid, and RNA polymerase II, IV, and V complexes. Studies of related genes in other species link the NF-YB family to drought tolerance, flowering time, and pathogen resistance.