Fig. 8. Proposed GLC functions in the FIS-regulation model for endosperm and embryo development. (A) Before fertilization, GLC promotes fertilization-independent endosperm development in a separate pathway opposing MEA and MSI1. Alternatively, MEA and MSI1 could prevent autonomous endosperm by repressing GLC. (B) After fertilization, maternal GLC directly or indirectly activates bi-parental PHE1, paternal RPS5a and paternal FAC1 to initiate embryo and endosperm proliferation independently of MEA-FIE or as a downstream repression target of MEA-FIE. Maternal MEA-FIE checks and balances this cellular proliferation by repressing maternal PHE1, MEIDOS and possibly maternal GLC.