UPSTREAM REGULATORY SEQUENCES FROM 2 BETA-CONGLYCININ GENES

Genes encoding the beta-conglycinin seed storage proteins of soybean a re expressed only in seeds during specific stages of development. The different subunits of beta-conglycinin, alpha', alpha and beta, are en coded by distinct members of a gene family. Yet there are marked diffe rences in the regulation of the genes encoding the alpha'/alpha and be ta subunits. Previous work (Chen et al., EMBO J 7: 297-302, 1988) iden tified a seed specific transcriptional enhancer upstream of a gene enc oding the alpha' subunit. Mutations were made within this region to di scern its functional components. Among those identified is a 62 bp reg ion (between -77 and -140) that contains a vicilin box consensus seque nce as well as a sequence that binds the soybean nuclear factor SEF4 i n vitro. A second region, which contains a sequence homologous to the core of the legumin box consensus (i.e., CATGCAT-like or RY repeat ele ment) at -246, was also shown to affect the activity of this enhancer in transgenic plants. A series of 5' terminal deletions were used to i dentify regulatory elements upstream of the beta subunit gene. Two reg ions were identified (from -553 to -442 and from -308 to -72) that, wh en deleted, led to a marked reduction in gene expression. Both of thes e elements contain sequences that bind SEF4 in vitro. The distal eleme nt also contains an AT-rich segment that recognizes a second nuclear f actor, SEF1, in vitro. Neither of these elements contains any homology to the vicilin box consensus.