Limits...
The repertoire of equine intestinal alpha-defensins.

Bruhn O, Paul S, Tetens J, Thaller G - BMC Genomics (2009)

Bottom Line: These effector molecules of the innate immune system act as endogenous antibiotics to protect the organism against infections with pathogenic microorganisms.In other cases the same genomic exons were found in different transcripts.Interestingly, the peptides were not found in other species of the Laurasiatheria to date.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Animal Breeding and Husbandry, Christian-Albrechts-University of Kiel, Hermann-Rodewald-Strasse 6, D-24118 Kiel, Germany. obruhn@tierzucht.uni-kiel.de

ABSTRACT

Background: Defensins represent an important class of antimicrobial peptides. These effector molecules of the innate immune system act as endogenous antibiotics to protect the organism against infections with pathogenic microorganisms. Mammalian defensins are classified into three distinct sub-families (alpha-, beta- and theta-defensins) according to their specific intramolecular disulfide-bond pattern. The peptides exhibit an antimicrobial activity against a broad spectrum of microorganisms including bacteria and fungi. Alpha-Defensins are primarily synthesised in neutrophils and intestinal Paneth cells. They play a role in the pathogenesis of intestinal diseases and may regulate the flora of the intestinal tract. An equine intestinal alpha-defensin (DEFA1), the first characterised in the Laurasiatheria, shows a broad antimicrobial spectrum against human and equine pathogens. Here we report a first investigation of the repertoire of equine intestinal alpha-defensins. The equine genome was screened for putative alpha-defensin genes by using known alpha-defensin sequences as matrices. Based on the obtained sequence information, a set of oligonucleotides specific to the alpha-defensin gene-family was designed. The products generated by reverse-transcriptase PCR with cDNA from the small intestine as template were sub-cloned and numerous clones were sequenced.

Results: Thirty-eight equine intestinal alpha-defensin transcripts were determined. After translation it became evident that at least 20 of them may code for functional peptides. Ten transcripts lacked matching genomic sequences and for 14 alpha-defensin genes apparently present in the genome no appropriate transcript could be verified. In other cases the same genomic exons were found in different transcripts.

Conclusions: The large repertoire of equine alpha-defensins found in this study points to a particular importance of these peptides regarding animal health and protection from infectious diseases. Moreover, these findings make the horse an excellent species to study biological properties of alpha-defensins. Interestingly, the peptides were not found in other species of the Laurasiatheria to date. Comparison of the obtained transcripts with the genomic sequences in the current assembly of the horse (EquCab2.0) indicates that it is yet not complete and/or to some extent falsely assembled.

Show MeSH

Related in: MedlinePlus

Alignment of 38 different α-defensin amino acid sequences. Fig. 1 represents the conserved amino acid residues and distinguishes potentially active peptides from pseudogenes. Conserved amino acid residues in the signal peptides present in all sequences were highlighted in grey. Conserved cysteine residues were highlighted in red, conserved arginine and glutamic acid residues, necessary for the intramolecular salt bridge were highlighted in blue, the conserved glycine residue, necessary for correct folding is highlighted in yellow. The previously known α-defensins DEFA1 and DEFA5L are written in red, defensin-like peptides (pseudogenes) in blue.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC2803202&req=5

Figure 1: Alignment of 38 different α-defensin amino acid sequences. Fig. 1 represents the conserved amino acid residues and distinguishes potentially active peptides from pseudogenes. Conserved amino acid residues in the signal peptides present in all sequences were highlighted in grey. Conserved cysteine residues were highlighted in red, conserved arginine and glutamic acid residues, necessary for the intramolecular salt bridge were highlighted in blue, the conserved glycine residue, necessary for correct folding is highlighted in yellow. The previously known α-defensins DEFA1 and DEFA5L are written in red, defensin-like peptides (pseudogenes) in blue.

Mentions: The 35 amino acid sequences of the first evaluation method were aligned with the 34 sequences obtained with the second evaluation method and peptides with an identity of 100% were combined. An alignment of the resulting 38 different peptide sequences is shown in Fig. 1 and Fig. 2. Table 3 shows the number of obtained clones along with the cDNA sequences corresponding to the amino acid sequences shown in Fig. 1 and Fig. 2 and the accession numbers of the equine α-defensin transcripts.


The repertoire of equine intestinal alpha-defensins.

Bruhn O, Paul S, Tetens J, Thaller G - BMC Genomics (2009)

Alignment of 38 different α-defensin amino acid sequences. Fig. 1 represents the conserved amino acid residues and distinguishes potentially active peptides from pseudogenes. Conserved amino acid residues in the signal peptides present in all sequences were highlighted in grey. Conserved cysteine residues were highlighted in red, conserved arginine and glutamic acid residues, necessary for the intramolecular salt bridge were highlighted in blue, the conserved glycine residue, necessary for correct folding is highlighted in yellow. The previously known α-defensins DEFA1 and DEFA5L are written in red, defensin-like peptides (pseudogenes) in blue.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2803202&req=5

Figure 1: Alignment of 38 different α-defensin amino acid sequences. Fig. 1 represents the conserved amino acid residues and distinguishes potentially active peptides from pseudogenes. Conserved amino acid residues in the signal peptides present in all sequences were highlighted in grey. Conserved cysteine residues were highlighted in red, conserved arginine and glutamic acid residues, necessary for the intramolecular salt bridge were highlighted in blue, the conserved glycine residue, necessary for correct folding is highlighted in yellow. The previously known α-defensins DEFA1 and DEFA5L are written in red, defensin-like peptides (pseudogenes) in blue.
Mentions: The 35 amino acid sequences of the first evaluation method were aligned with the 34 sequences obtained with the second evaluation method and peptides with an identity of 100% were combined. An alignment of the resulting 38 different peptide sequences is shown in Fig. 1 and Fig. 2. Table 3 shows the number of obtained clones along with the cDNA sequences corresponding to the amino acid sequences shown in Fig. 1 and Fig. 2 and the accession numbers of the equine α-defensin transcripts.

Bottom Line: These effector molecules of the innate immune system act as endogenous antibiotics to protect the organism against infections with pathogenic microorganisms.In other cases the same genomic exons were found in different transcripts.Interestingly, the peptides were not found in other species of the Laurasiatheria to date.

View Article: PubMed Central - HTML - PubMed

Affiliation: Institute of Animal Breeding and Husbandry, Christian-Albrechts-University of Kiel, Hermann-Rodewald-Strasse 6, D-24118 Kiel, Germany. obruhn@tierzucht.uni-kiel.de

ABSTRACT

Background: Defensins represent an important class of antimicrobial peptides. These effector molecules of the innate immune system act as endogenous antibiotics to protect the organism against infections with pathogenic microorganisms. Mammalian defensins are classified into three distinct sub-families (alpha-, beta- and theta-defensins) according to their specific intramolecular disulfide-bond pattern. The peptides exhibit an antimicrobial activity against a broad spectrum of microorganisms including bacteria and fungi. Alpha-Defensins are primarily synthesised in neutrophils and intestinal Paneth cells. They play a role in the pathogenesis of intestinal diseases and may regulate the flora of the intestinal tract. An equine intestinal alpha-defensin (DEFA1), the first characterised in the Laurasiatheria, shows a broad antimicrobial spectrum against human and equine pathogens. Here we report a first investigation of the repertoire of equine intestinal alpha-defensins. The equine genome was screened for putative alpha-defensin genes by using known alpha-defensin sequences as matrices. Based on the obtained sequence information, a set of oligonucleotides specific to the alpha-defensin gene-family was designed. The products generated by reverse-transcriptase PCR with cDNA from the small intestine as template were sub-cloned and numerous clones were sequenced.

Results: Thirty-eight equine intestinal alpha-defensin transcripts were determined. After translation it became evident that at least 20 of them may code for functional peptides. Ten transcripts lacked matching genomic sequences and for 14 alpha-defensin genes apparently present in the genome no appropriate transcript could be verified. In other cases the same genomic exons were found in different transcripts.

Conclusions: The large repertoire of equine alpha-defensins found in this study points to a particular importance of these peptides regarding animal health and protection from infectious diseases. Moreover, these findings make the horse an excellent species to study biological properties of alpha-defensins. Interestingly, the peptides were not found in other species of the Laurasiatheria to date. Comparison of the obtained transcripts with the genomic sequences in the current assembly of the horse (EquCab2.0) indicates that it is yet not complete and/or to some extent falsely assembled.

Show MeSH
Related in: MedlinePlus