Molecular characterization of a stigma-specific gene encoding an arabinogalactan-protein (AGP) from Nicotiana alata

Abstract

Arabinogalactan-proteins (AGPs) were isolated from the pistils of Nicotiana alata, deglycosylated, and the protein backbones fractionated by reversed-phase HPLC as previously reported. A major fraction, RT35 was isolated and peptide sequences were obtained after protease digestion. A gene-specific degenerate oligonucleotide was designed according to the amino acid sequences and a 380 bp PCR fragment was amplified in vitro from pistil RNA. The PCR fragment was used to screen a pistil cDNA library and a 762 bp cDNA clone (AGPNa3) was isolated and sequenced. The AGPNa3 cDNA encodes a 169 amino acid protein which consists of three domains: an N-terminal secretion signal, a Pro-rich domain and a ..