Submitted to: Cattle: Domestication, Disease and Environment
Publication Type: Review Article
Publication Acceptance Date: July 17, 2012
Publication Date: May 10, 2013
Citation: Liu, G., Bickhart, D.M. 2013. The trappin gene famliy: structue, function and evolution. Cattle: Domestication, Disease and Environment. p. 25-38.
Interpretive Summary: Trappins are a family of small secretary host-defense peptides that have many functions. This book chapter reviews trappin genes, protein structures and functions; examines their roles in mammalian evolution and domestication and concludes with their therapeutic potentials in human and animal health. Farmers, Scientist, and policy planners who need improve animal health and production based on genome-enable animal selection will benefit from this chapter.
Trappins are a family of small secretary host-defense peptides that have many functions. Most members exhibit antiprotease and antimicrobial activities, while others influence inflammation, immunity and the promotion of tissue repair. Considered to be important guardians of mucosal surfaces, trappins possess an N-terminal transglutaminase substrate (TGS) domain and a C-terminal whey acidic protein (WAP) four-disulphide core (WFDC) domain. The numbers and compositions of trappin genes vary among eutherian mammalian species. While there is a single trappin-2 gene in human and sheep, no trappin gene was found in mouse and rat. By contrast, multiple duplicated trappin paralogs were found in pig, cattle, guinea pig, armadillo and Afrotherian species (elephant, tenrec, and hyrax). Trappin duplication events appear to have occurred independently in these mammalian lineages over a long time period, suggesting their potential roles in species formation and animal domestication. Recent duplication and accelerated evolution of trappin genes in pig, cattle and armadillo demonstrate that mammalian genomes have the capability to form trappin multigenes to acquire antimicrobial activities for niche-specific pathogens.