title: Isolation and characterization of two wound-regulated tomato extensin genes.
abstract: Extensins comprise a family of structural cell wall hydroxyproline-rich glycoproteins in plants. Two tomato genomic clones, Tom J-10 and Tom L-4, were isolated from a tomato genomic DNA library by in situ plaque hybridization with extensin DNA probes. Tom J-10 encoded an extensin with 388 amino acid residues and a predicted molecular mass of 43 kDa. The Tom J-10 encoded extensin lacked a typical signal peptide sequence, but contained two distinct protein domains consisting of 19 tandem repeats of Ser-Pro4-Ser-Pro-Lys-Tyr-Val-Tyr-Lys at the amino terminus which were directly followed by 8 tandem repeats of the consensus sequence Ser-Pro4-Tyr3-Lys-Ser-Pro4-Ser-Pro at the carboxy terminus. RNA blot hybridization analysis with the Tom J-10 extensin probe demonstrated the presence of a 4.0 kb tomato stem mRNA which accumulated markedly in response to wounding. Tom L-4 encoded an extensin with 322 amino acid residues and a predicted molecular mass of 35 kDa. The Tom L-4 encoded extensin contained a typical signal peptide sequence at the amino terminus and was followed by at least 3 distinct domains. These domains consisted of an amino terminal domain containing several Lys-Pro and Ser-Pro4 repeat units, a central domain with repeats of the consensus sequence Ser-Pro2-5-Thr-Pro-Ser-Tyr-Glu-His-Pro-Lys-Thr-Pro, and a carboxy terminal domain containing repeats of the consensus sequence Ser-Ser-Pro4-Ser-Pro-Ser-Pro4-Thr-Tyr1-3. RNA blot hybridization analysis with the Tom L-4 extensin probe demonstrated the presence of a 2.6 kb tomato stem mRNA which accumulated in response to wounding.
authors.affiliation: Department of Botany, Ohio University, Athens 45701.
authors.forename: J
authors.initials: J
authors.lastname: Zhou
authors.forename: D
authors.initials: D
authors.lastname: Rumeau
authors.forename: A M
authors.initials: AM
authors.lastname: Showalter
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D015139:Blotting, Southern; D002473:Cell Wall / Q000502:physiology; D003001:Cloning, Molecular; D004247:DNA / Q000235:genetics* / Q000302:isolation & purification; D015342:DNA Probes; D005786:Gene Expression Regulation; D006023:Glycoproteins / Q000235:genetics*; D008969:Molecular Sequence Data; D005810:Multigene Family; D018521:Plant Physiological Phenomena; D010940:Plant Proteins / Q000235:genetics*; D010944:Plants / Q000235:genetics*; D011487:Protein Conformation; D012313:RNA / Q000235:genetics / Q000302:isolation & purification; D015183:Restriction Mapping; D012689:Sequence Homology, Nucleic Acid; D014947:Wounds and Injuries
chemical_list: D015342:DNA Probes; D006023:Glycoproteins; D010940:Plant Proteins; C005488:extensin protein, plant; D012313:RNA; D004247:DNA