Monoclonal antibodies to barley aleurain and homologs from other plants

• Published in: The Plant journal : for cell and molecular biology 1997-06, Vol.11 (6), p.1359-1368
• Main Authors: Rogers, Sally W., Burks, Marlyn, Rogers, John C.
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Antibodies, Monoclonal - immunology; Antigen-Antibody Reactions; Arabidopsis; Biological and medical sciences; Cloning, Molecular; Conserved Sequence; Cysteine Endopeptidases - genetics; Cysteine Endopeptidases - immunology; Enzymes; Fundamental and applied biological sciences. Psychology; Hordeum - immunology; Hordeum vulgare; Hybridomas; Hydrogen-Ion Concentration; Metabolism; Microscopy, Confocal; Microscopy, Fluorescence; Molecular Sequence Data; Nicotiana tabacum; Petunia; Plant physiology and development; Recombinant Proteins - genetics; Recombinant Proteins - isolation & purification
• ISSN: 0960-7412; 1365-313X
• DOI: 10.1046/j.1365-313X.1997.11061359.x

Barley aleurain is contained within a specific type of vacuole characterized by acidic pH and the presence of other hydrolytic enzymes. The aleurain‐containing vacuole is distinct from protein storage vacuoles, and anti‐aleurain antibodies serve as markers for this organelle in barley cells. Aleurain is a unique type of cysteine protease, and other plant species have genes for homologs whose sequences are highly conserved, but little is known about these homologs at the protein level. Seven monoclonal antibodies to barley aleurain were isolated, which bind to and define aleurain homologues in Arabidopsis, Petunia, and tobacco cell extracts. Interestingly, in addition to 29–32 kDa aleurain homologs, Petunia extracts contain a protein of ∼50 kDa and tobacco extracts a protein of ∼40 kDa that are recognized by multiple different mono‐clonal antibodies, indicating an unexpected diversity to the aleurain protein family. Among the group of antibodies are some that efficiently immunoprecipitate metabolically labeled aleurain from barley cell extracts, and some that efficiently label aleurain in immunofluorescence assays using root tip cells. These antibodies should be useful for plant cell biologists who study vacuole biogenesis and function and sorting of proteins to specific vacuolar compartments, in barley as well as other plant species.