Expression of two sucrose synthetase genes in endosperm and seedling cells of maize: evidence of tissue specific polymerization of protomers

Post-Transcriptional Control of Sucrose Synthase Expression in Anaerobic Seedlings of Maize

“…2B, lane 4). An equal level of in vivo expression of these two genes in maize seedling roots has been described previously (5). The SS proteins translated from anaerobically stressed root and kernel RNAs did not differ significantly in apparent mol wt and reacted with SS1 antibody.…”

“…The Sh gene is highly expressed in the developing endosperm resulting in abundant levels ofboth the SSl transcript and the SSl protein (3). The Sus encoded SS2 isozyme is detectable in many parts of the plant including the embryo and endosperm (5). The two isozymes are biochemically similar and share immunological cross-reactivity (3,8).…”

“…In approximately equal levels, subunits of SSl and SS2 proteins copolymerize to yield a total of five isozymes comprised of two homotetrameric and three heterotetrameric forms (5). The sh mutant lacking the SS1 protein and a Sus-null mutant lacking the SS2 protein contain only the SS1 or SS2 homotetramers, respectively (4).…”

“…SDS-PAGE was done by the method of Laemmli (17). Immunoblot analysis was done as described previously (5); primary antisera in these analyses were raised against purified SS 1 protein ( 19). Fluorography was done by soaking the gel in 1.5 M sodium salicylate for 30 min, and exposing the dried gel to x-ray film.…”

Purification and Characterization of Sucrose Synthase from the Cotyledons of Vicia faba L

“…In maize, a total of five SS isozymes have been identified (19). Developing endosperm cells contain the two homotetramers (SlSlSlS1 and S2S2S2S2), whereas in young roots and shoots, the three heterotetramers are also present (5). Similarly, five isozymes have been detected in sorghum but, in contrast to maize, both SS genes are expressed simultaneously in the endosperm, leading 'Abbreviations: SS, sucrose synthase; Vo, void volume; pL, isoelectric point; V8, endoprotease Glu-C from Staphylococcus aureus V8; Arg-C, endoprotease Arg-C from mice glands.…”