The loss-of-function mutation of the RGE1 (retarded growth of embryo) gene, which is expressed during seed development, caused small and shriveled seeds. The embryo of the loss-of-function mutant showed retarded growth after the heart stage although abnormal morphogenesis and pattern formation of the embryo and endosperm was not observed. RGE1 expression was determined in endosperm cells using the β-glucuronidase reporter gene and RT-PCR. The differences of expression profile between rge1-1 and wild type Col-0 was examined to know the functions of RGE1. The result of Microarray analysis showed specific down-regulation of putative GDSL motif lipase genes in the rge1-1 mutant indicating possible involvement of these genes in seed morphology. Experiment Overall Design: Total RNA was isolated from siliques of rge1-1 and wild type at 12 DAF using an RNAqueous Kit (Ambion, Inc, USA).