Plant Molecular Biology

, Volume 41, Issue 3, pp 403–414 | Cite as

Evidence for factors regulating transfer cell-specific expression in maize endosperm

  • Gregorio Hueros
  • Joaquin Royo
  • Monika Maitz
  • Francesco Salamini
  • Richard D. Thompson
Article

Abstract

In maize, a layer of basal endosperm cells adjacent to the pedicel is modified for a function in solute transfer. Three genes specifically expressed in this region, termed the basal endosperm transfer layer (BETL-2 to -4), were isolated by differential hybridization. BETL-2 to -4 are coordinately expressed in early and mid-term endosperm development, but are absent at later stages. BETL-2 to -4 coding sequences all predict small (<100 amino acids), secreted, cysteine-rich polypeptides which lack close relatives in current database accessions. BETL-3 and BETL-1 display some sequence similarities with each other and to plant defensins. BETL-2 to -4 promoter regions were isolated and compared, revealing the presence of a promoter-proximal microsatellite repeat as the most highly conserved sequence element in each sequence. Electrophoretic mobility shift assays (EMSA) showed that specific BETL-2 to -4 promoter fragments competed for binding to the same DNA-binding activity in nuclear extracts prepared from maize endosperm. Although BETL-2 to -4 are only expressed in basal endosperm cells, the DNA-binding activities detected were of two types: distal endosperm-specific, or present in both basal and distal endosperm extracts. On the basis of these findings, a model to account for the coordinate regulation of BETL genes in endosperm cells is proposed.

BETL endosperm maize promoter transfer cell 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

Copyright information

© Kluwer Academic Publishers 1999

Authors and Affiliations

  • Gregorio Hueros
    • 1
  • Joaquin Royo
    • 2
  • Monika Maitz
    • 1
  • Francesco Salamini
    • 1
  • Richard D. Thompson
    • 1
  1. 1.MPI für Züchtungsforschung, Carl-von-Linné Weg 10KölnGermany
  2. 2.Dpto. Biología Celular y GeneticaUniversity AlcalaAlcala de HenaresSpain

Personalised recommendations