Genomic organization and classification of the bovine WC1 genes and expression by peripheral blood gamma delta T cells
BMC GENOMICS
Authors: Herzig, Carolyn T. A.; Baldwin, Cynthia L.
Abstract
Background: WC1 co-receptors are group B scavenger receptor cysteine-rich molecules that are found exclusively on gamma delta T cells and are thought to be encoded by a multi-gene family. Previous studies have shown gamma delta T cells that respond to a particular stimulus have unique WC1 molecules expressed. Prior to the onset of the studies described here only one full-length WC1 nucleotide sequence was publicly available, though three WC1 molecules had been distinguished based on monoclonal antibody reactivity. Furthermore, the number of WC1 genes found in the bovine genome and their sequences had not yet been resolved. Results: By annotating the bovine genome Btau_3.1 assembly, here we show the existence of 13 members in the WC1 gene family and their organization within two loci on chromosome 5 including three distinct exon-intron gene structures one of which coded for a potentially more primitive and smaller WC1 molecule that is similar to the swine WC1 gene. We also provide cDNA evidence as verification for many of the annotated sequences and show transcripts for isoforms derived by alternative splicing. Conclusion: It is possible that WC1 diversity contributes to functional differences that have been observed between gamma delta T cell populations. The studies described here demonstrate that WC1 molecules are encoded by a large, multi-gene family whose transcripts undergo extensive alternative splicing. Similar to other non-rearranging immunoreceptors, it is likely that the WC1 gene repertoire underwent expansion in order to keep pace with rapidly changing ligands.
An Arabidopsis berberine bridge enzyme-like protein specifically oxidizes cellulose oligomers and plays a role in immunity
PLANT JOURNAL
Authors: Locci, Federica; Benedetti, Manuel; Pontiggia, Daniela; Citterico, Matteo; Caprari, Claudio; Mattei, Benedetta; Cervone, Felice; De Lorenzo, Giulia
Abstract
The plant cell wall is the barrier that pathogens must overcome to cause a disease, and to this end they secrete enzymes that degrade the various cell wall components. Due to the complexity of these components, several types of oligosaccharide fragments may be released during pathogenesis and some of these can act as damage-associated molecular patterns (DAMPs). Well-known DAMPs are the oligogalacturonides (OGs) released upon degradation of homogalacturonan and the products of cellulose breakdown, i.e. the cellodextrins (CDs). We have previously reported that four Arabidopsis berberine bridge enzyme-like (BBE-like) proteins (OGOX1-4) oxidize OGs and impair their elicitor activity. We show here that another Arabidopsis BBE-like protein, which is expressed coordinately with OGOX1 during immunity, specifically oxidizes CDs with a preference for cellotriose (CD3) and longer fragments (CD4-CD6). Oxidized CDs show a negligible elicitor activity and are less easily utilized as a carbon source by the fungus Botrytis cinerea. The enzyme, named CELLOX (cellodextrin oxidase), is encoded by the gene At4g20860. Plants overexpressing CELLOX display an enhanced resistance to B. cinerea, probably because oxidized CDs are a less valuable carbon source. Thus, the capacity to oxidize and impair the biological activity of cell wall-derived oligosaccharides seems to be a general trait of the family of BBE-like proteins, which may serve to homeostatically control the level of DAMPs to prevent their hyperaccumulation. Significance Statement This paper uncovers the activity of a member of the gene family encoding the berberine bridge enzyme-like (BBE-like) proteins. It encodes a specific oxidase that impairs the damage-associated molecular pattern (DAMP) activity of cellodextrins and plays a role in immunity. The oxidation and inactivation of DAMPs seem to be general and important functions of several BBE-like proteins and this work opens up avenues for the study of the physiological role and evolution of this family.