THE PLANT CELL, Vol 4, Issue 4 413-423, Copyright © 1992 by American Society of Plant Biologists
A Maize Embryo-Specific Gene Encodes a Proline-Rich and Hydrophobic Protein
M. Jose-Estanyol, L. Ruiz-Avila and P. Puigdomenech
Departament de Genetica Molecular, Centre d'Investigacio i Desenvolupament-Consejo Superior de Investigaciones Cientificas, Jordi Girona 18, 08034 Barcelona, Spain
A gene from maize that encodes a hybrid proline-rich protein (HyPRP) formed
by two well-defined domains, proline-rich and hydrophobic, respectively,
has been characterized at the level of its structure and expression. The
proline-rich domain is composed of elements PPYV and PPTPRPS, similar to
those found in PRP proteins from soybean. The hydrophobic domain is rich in
cysteine and is similar to seed proteins, mainly to a soybean hydrophobic
seed protein. In maize, HyPRP is encoded by a single gene, and its mRNA
accumulates in immature maize zygotic embryos, with a maximum accumulation
between 12 and 18 days after pollination. The HyPRP mRNA can also be
detected in ovary prior to pollination. In situ hybridization experiments
on embryo sections show an expression of the gene in scutellum and in
nonvascular cells from the embryo axis. Functional hypotheses related to
HyPRP are discussed.
