Abstract

Coordination of cell growth and cell division is very important for living organisms in order for these to develop harmonically. The present research is concerned with the purification and characterization of a new peptide hormone, namely ZmIGF (Zea mays insulin-like growth factor), which regulates growth and cell division in maize tissues. ZmIGF is a peptide of 5.7 kDa, as determined by mass spectroscopy. It was isolated either from maize embryonic axes of 48-h germinated seeds or from embryogenic callus and purified through several chromatographic procedures to obtain a single peak as shown by Reverse Phase High-Performance Liquid Chromatography (RP-HPLC). This peptide exhibits a well defined α-helix structure by circular dichroism analysis, similar to that reported for Insulin or for Insulin-like growth factor (IGF-1). Further, ZmIGF seems to perform, in maize, a similar function to that reported for insulin or peptides from the IGF family in animals. Indeed, maize tissues stimulated either by ZmIGF or insulin showed to induce selective synthesis of ribosomal proteins as well as of DNA. Taken together, the previously mentioned data strongly suggest that plants contain a peptide hormone of the IGF family, highly conserved through evolution that regulates growth and development.

Keywords: Cell growth and cell division, Insulin-like growth factor, Plant peptide hormone, Zea mays L, ZmIGF (Zea mays insulin-like growth factor), maize tissues, Reverse Phase High-Performance Liquid Chromatography (RP-HPLC), (IGF-1), ZmIGF, IGF family, Insulin-like growth factors (IGFs), ligand-receptor interaction, structure-activity relationships, insulin-like peptide, non-photosynthetic eukaryotes, Target of Rapamycin (TOR) kinase, TOR-S6K, Zea maize embryo, anion-exchange chromatography, Poly-Prep columns, Dot Blot Assay, SDS-PAGE Gel, liquid scintillation counter, [3H]-thymidine, Minneapolis, mild trypsin digestion, SDS-PAGE, Carboxy Methyl Sepharose Chromatogram, LC-MS/MS, non-embryogenic calli, germinating seeds, maize embryogenic calli, alpha helix, ribosomal proteins synthesis, self-incompatibility, human insulin antibodies, post-translationallyCell growth and cell division, Insulin-like growth factor, Plant peptide hormone, Zea mays L, ZmIGF (Zea mays insulin-like growth factor), maize tissues, Reverse Phase High-Performance Liquid Chromatography (RP-HPLC), (IGF-1), ZmIGF, IGF family, Insulin-like growth factors (IGFs), ligand-receptor interaction, structure-activity relationships, insulin-like peptide, non-photosynthetic eukaryotes, Target of Rapamycin (TOR) kinase, TOR-S6K, Zea maize embryo, anion-exchange chromatography, Poly-Prep columns, Dot Blot Assay, SDS-PAGE Gel, liquid scintillation counter, [3H]-thymidine, Minneapolis, mild trypsin digestion, SDS-PAGE, Carboxy Methyl Sepharose Chromatogram, LC-MS/MS, non-embryogenic calli, germinating seeds, maize embryogenic calli, alpha helix, ribosomal proteins synthesis, self-incompatibility, human insulin antibodies, post-translationally