Julia Dorin’s focus is on host defence peptides. It has become clear to me that the dysregulation of innate immunity processes can lead to the destructive inflammation central to many (all) human diseases. Currently I am working on a multigene family of antimicrobial peptides called β-defensins which are astonishingly potent against yeast, bacteria and viruses and recognised as major players in innate immunity and yet deletion of these genes results in novel and exciting phenotypes. They are expressed at mucosal surfaces when induced but are highly expressed normally in male and female reproductive tract. I have shown that these molecules are both important in protection from infection and in immune modulation in vitro and in vivo. I have recently developed single gene, clade specific and whole locus deletions of these genes to reveal their full in vivo functional repertoire. I have just published (Zhou et al 2013 (over 1,000 downloads in the first 2 weeks of publication) the profound male infertility phenotype we observe when a subset of defensin genes are deleted and reveal a novel function of these genes in sperm maturation and control of calcium influx into sperm cells. This cluster of b-defensins in human (but not in mouse) is highly copy number variable (varies between 1 and 16 in human populations). The mutant derived sperm are precociously activated and show microtubule disruption and lack of motility. Deletion of the whole 31 gene locus is revealing a diverse series of inflammatory phenotypes and I am investigating their relevance to human disease.
My other key interest has been in the use of ES cell technology to determine the in vivo function of genes and to enable the development of mice as disease models for translational research. I have been involved in the creation of many useful models including cystic fibrosis, the infertility gene Dazla, RNAse H2, and VPAC(2) receptor among others and now enable others to grow ES cells and develop their mouse models.