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ARS Home » Research » Publications at this Location » Publication #93898
Title: AN INSULIN-STIMULATED SIGNAL TRANSDUCTION PATHWAY REGULATES PROTEIN SYNTHESIS IN MAIZE TISSUES

Author
item SANCHEZ, ESTELA - NACIONAL AUTONOMA MEXICO
item BELTRAN-PENA, ELDA - NACIONAL AUTONOMA MEXICO
item Ortiz Lopez, Adriana

Submitted to: Physiologia Plantarium
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/9/1998
Publication Date: N/A
Citation: N/A

Interpretive Summary: During seed development, information is transferred from the maternal parent to the seed that is vital for the early events in seed germination. This information is transferred from genes in the parent plant and stored in the dried seed in the form of messenger RNA, the biological blueprint for the construction of proteins. There is a great deal of importance in determining mechanisms that regulate when these blueprints are used to make specific proteins required for the ordered sequence of events in germination. In this study we made the very unexpected discovery that a compound structurally very similar to vertebrate insulin is involved in controlling when these blueprints are used during seed germination. These results provide evidence for a completely unexpected mode of regulation in plants. These findings are important to a wide range of agricultural scientists interested in the control of seed germination under stresses such as flooded or cold soils.

Technical Abstract: The presence of insulin accelerated maize seed germination and seedling growth. Insulin-simulated maize axes showed enhancement of [**35S-] methionine incorporation into ribosomal proteins and mobilization of S6 ribosomal protein mRNA into polysomes. Increased in S6 ribosomal protein phosphorylation of the small ribosomal subunit (40S) was observed in [**32P-] orthophosphate pulse-labeled experiments when maize axes were simulated by insulin. Application of either wortmannin or rapamycin, inhibitors of protein kinases of the insulin transduction pathway, abolished the insulin stimulatory effect on S6 ribosomal protein phosphorylation and on ribosomal protein synthesis. The presence of an endogenous insulin-like peptide was detected in maize tissues by immunological techniques. The above data are interpreted as indication of the existence of an insulin-dependent signal transduction pathway in maize tissues involved in the regulation of translation.