title: Salmonella Typhi shdA: pseudogene or allelic variant?
abstract: ShdA from Salmonella Typhimurium (ShdASTm) is a large outer membrane protein that specifically recognizes and binds to fibronectin. ShdASTm is involved in the colonization of the cecum and the Peyer's patches of terminal ileum in mice. On the other hand, shdA gene from Salmonella Typhi (shdASTy) has been considered a pseudogene (i.e. a nonfunctional sequence of genomic DNA) due to the presence of deletions and mutations that gave rise to premature stop codons. In this work we show that, despite the deletions and mutations, shdASTy is fully functional. S. Typhi ΔshdA mutants presented an impaired adherence and invasion of HEp-2 pre-treated with TGF-β1, an inducer of fibronectin production. Moreover, shdA from S. Typhi and S. Typhimurium seem to be equivalent since shdASTm restored the adherence and invasion of S. Typhi ΔshdA mutant to wild type levels. In addition, anti-FLAG mAbs interfered with the adherence and invasion of the S. Typhi shdA-3xFLAG strain. Finally, shdASTy encodes a detectable protein when heterologously expressed in Escherichia coli DH5α. The data presented here show that shdASTy is not a pseudogene, but a different functional allele compared with shdASTm.
authors.affiliation: Facultad de Ciencias Biológicas, Universidad Andres Bello, República 217, Santiago de Chile, Chile. Electronic address: i.urrutia@uandresbello.edu.
authors.forename: I M
authors.initials: IM
authors.lastname: Urrutia
authors.affiliation: Facultad de Ciencias Biológicas, Universidad Andres Bello, República 217, Santiago de Chile, Chile. Electronic address: jfuentes@unab.cl.
authors.forename: J A
authors.initials: JA
authors.lastname: Fuentes
authors.affiliation: Facultad de Ciencias Biológicas, Universidad Andres Bello, República 217, Santiago de Chile, Chile. Electronic address: lu.valenzuela.v@uandresbello.edu.
authors.forename: L M
authors.initials: LM
authors.lastname: Valenzuela
authors.affiliation: Facultad de Ciencias Biológicas, Universidad Andres Bello, República 217, Santiago de Chile, Chile. Electronic address: all.ortega@uandresbello.edu.
authors.forename: A P
authors.initials: AP
authors.lastname: Ortega
authors.affiliation: Facultad de Ciencias Biológicas, Universidad Andres Bello, República 217, Santiago de Chile, Chile. Electronic address: alejandro.a.hidalgo@gmail.com.
authors.forename: A A
authors.initials: AA
authors.lastname: Hidalgo
authors.affiliation: Facultad de Medicina, Universidad Andres Bello, República 330, Santiago de Chile, Chile. Electronic address: gmora@unab.cl.
authors.forename: G C
authors.initials: GC
authors.lastname: Mora
mesh_terms: D000483:Alleles; D000595:Amino Acid Sequence; D001422:Bacterial Adhesion / Q000235:genetics; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry / Q000235:genetics*; D002460:Cell Line; D019295:Computational Biology; D014644:Genetic Variation; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D016366:Open Reading Frames; D011544:Pseudogenes; D012485:Salmonella typhi / Q000235:genetics* / Q000472:pathogenicity; D016415:Sequence Alignment; D037521:Virulence Factors / Q000235:genetics
chemical_list: D001425:Bacterial Outer Membrane Proteins; C409034:ShdA protein, Salmonella enterica; D037521:Virulence Factors
keywords: Fibronectin; Host-specificity; Pseudogene; ShdA