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Abstract

Nicotiana alata has a style-specific hydroxyproline-rich glycoprotein (the 120 kDa glycoprotein) which has properties of both extensins and AGPs [19, 20]. The 120 kDa glycoprotein is a soluble component in the extracellular matrix of the transmitting tract of styles where it accounts for ca. 9% of the total buffer-soluble protein. Here we describe the molecular cloning of a cDNA representing the gene NaPRP5 which encodes the backbone of the 120 kDa glycoprotein. Expression of mRNA is restricted to styles, consistent with observations on the distribution of the 120 kDa glycoprotein. Levels of accumulation of the transcript encoding the 120 kDa protein backbone are not altered significantly by pollination with either compatible or incompatible pollen. The protein backbone of the 120 kDa glycoprotein, as predicted by the cDNA sequence, is composed of three distinct domains. The sequence of these domains, together with linkage analysis of the carbohydrate component of the 120 kDa glycoprotein, allows predictions of the likely distribution of substituent glycosyl chains along the protein backbone. The similarity of the C-terminal domains of the 120 kDa glycoprotein and GaRSGP, the galactose-rich style glycoprotein of N. alata, is consistent with the two molecules sharing a common antigenic domain in their backbones [31]. The sharing of domains between distinct hydroxyproline-rich glycoproteins suggests that identification of a glycoprotein of this class solely by its protein or carbohydrate epitope is not valid.

The Nicotiana sylvestris extensin gene, Ext 1.2A, is expressed in the root transition zone and upon wounding

“…2. Our working hypothesis was that recombination events occurred in Escherichia coli as discussed in previous publications [34,35]. Finally, the cloning of the central part of the coding region was successful when the oligonucleotide F located in between all the identified duplicated sequences was used together with the oligonucleotide D for PCR amplification.…”

“…RNAs were stored at a concentration of 0.1 µg/µL after phenol/chloroform extraction (v/v) and ethanol precipitation. Primer extension was performed in a 20 µL reaction volume with M-MLV (Moloney Murine Leukemia Virus) RT (Reverse Transcriptase) buffer (Promega), 2 mM dCTP, 2 mM dTTP, 2 mM dGTP, 4 µM dATP, 20 to 40 U RNase inhibitor (RNAguard inhibitor, porcine, Amersham Pharmacia Biotech UK Limited), 50 pmol oligonucleotide G ( Table 1) and 5 µCi [α- 35 S]dATP (>1000 Ci/mmol, Amersham Pharmacia Biotech UK Limited). Reaction was incubated for 3 min at 65°C to remove RNA secondary structures and then for 10 min at 37°C for primer annealing.…”

SCFSLF-mediated cytosolic degradation of S-RNase is required for cross-pollen compatibility in S-RNase-based self-incompatibility in Petunia hybrida

“…So far, three essential pistil-modifier factors, 120K (120 kDa glycoprotein), HT-B protein and NaStEP ( Nicotiana alata stigma expressed protein), have been identified in Nicotiana species (McClure et al, 1999; Hancock et al, 2005; Jimenez-Durán et al, 2013). 120K is a style-specific glycoprotein that is taken up by pollen tubes during pollination (Lind et al, 1996; Schultz et al, 1997). Suppression of 120K expression by RNAi prevents S -specific pollen rejection (Hancock et al, 2005).…”

Post-translational Modifications of Arabinogalactan-peptides of Arabidopsis thaliana

“…Additional proteolysis of chimeric (non-classical) AGPs has been experimentally observed in PcAGP2 from pear (33) and for the 120-kDa protein from ornamental tobacco (44). For the chimeric AGPs it is not known whether proteolysis occurs in vivo or during extraction of the proteins.…”