Required for the development of the one-cell zygote and endosperm in embryos (PubMed:15634699). Required for micropylar pollen tube guidance, but has no effect on ovule development and gametophytic cell fate specification. May connect transcription factors and the Pol II machinery to regulate pollen tube attraction, via its interactions with AGAMOUS-like (AGL) transcription factors, MEE14/CCG and the Mediator complex (PubMed:26462908). Homotetramer (PubMed:26462908). Interacts with MEE12/CCG, MED7A, MED7B, MED9, AGL49, AGL53, AGL75, AGL80, AGL81, AGL82, AGL103 and NRPB1 (via CTD) (PubMed:26462908). Expressed in roots, leaves, stems and flowers. Expressed in the central cell of mature ovules. Disrupted function of the female gametophyte. Defective in micropylar pollen tube guidance leading to zygotic lethality.