title: Cloning and characterization of the lectin cDNA clones from onion, shallot and leek.
abstract: Characterization of the lectins from onion (Allium cepa), shallot (A. ascalonicum) and leek (A. porrum) has shown that these lectins differ from previously isolated Alliaceae lectins not only in their molecular structure but also in their ability to inhibit retrovirus infection of target cells. cDNA libraries constructed from poly(A)-rich RNA isolated from young shoots of onion, shallot and leek were screened for lectin cDNA clones using colony hybridization. Sequence analysis of the lectin cDNA clones from these three species revealed a high degree of sequence similarity both at the nucleotide and at the amino acid level. Apparently the onion, shallot and leek lectins are translated from mRNAs of ca. 800 nucleotides. The primary translation products are preproproteins (ca. 19 kDa) which are converted into the mature lectin polypeptides (12.5-13 kDa) after post-translational modifications. Southern blot analysis of genomic DNA has shown that the lectins are most probably encoded by a family of closely related genes which is in good agreement with the sequence heterogeneity found between different lectin cDNA clones of one species.
authors.affiliation: Laboratory for Phytopathology and Plant Protection, Katholieke Universiteit Leuven, Belgium.
authors.forename: E J
authors.initials: EJ
authors.lastname: Van Damme
authors.forename: K
authors.initials: K
authors.lastname: Smeets
authors.forename: I
authors.initials: I
authors.lastname: Engelborghs
authors.forename: H
authors.initials: H
authors.lastname: Aelbers
authors.forename: J
authors.initials: J
authors.lastname: Balzarini
authors.forename: A
authors.initials: A
authors.lastname: Pusztai
authors.forename: F
authors.initials: F
authors.lastname: van Leuven
authors.forename: I J
authors.initials: IJ
authors.lastname: Goldstein
authors.forename: W J
authors.initials: WJ
authors.lastname: Peumans
mesh_terms: D000490:Allium / Q000235:genetics*; D000595:Amino Acid Sequence; D000998:Antiviral Agents / Q000494:pharmacology; D001483:Base Sequence; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000235:genetics; D016678:Genome; D037102:Lectins / Q000235:genetics* / Q000378:metabolism / Q000494:pharmacology; D008358:Mannose / Q000378:metabolism; D008969:Molecular Sequence Data; D037121:Plant Lectins; D011061:Poly A / Q000302:isolation & purification; D011499:Protein Processing, Post-Translational; D012333:RNA, Messenger / Q000302:isolation & purification; D012190:Retroviridae / Q000187:drug effects; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D012689:Sequence Homology, Nucleic Acid; D013045:Species Specificity
chemical_list: D000998:Antiviral Agents; D018076:DNA, Complementary; D037102:Lectins; D037121:Plant Lectins; D012333:RNA, Messenger; D011061:Poly A; D008358:Mannose