Dr. Xinguo Chen's research is centered on identifying the roles of an abundant class of ribonucleoproteins (RNPs), known as Ro60 RNPs, which are widespread in animal cells and also present in many bacteria. Ro60 RNPs were discovered because the major protein, the ring-shaped Ro 60 kDa autoantigen (Ro60), is a clinically important target of autoantibodies in patients with systemic lupus erythematosus. In all organisms examined, Ro60 binds ~100 nt noncoding RNAs called Y RNAs. Because Ro60 is not present in yeast, he used the first bacterium with an ortholog, Deinococcus radiodurans, as a model organism. He discovered that the bacterial and mammalian Ro60 proteins contribute to cell survival following ultraviolet (UV) irradiation, and that the bacterial ortholog functions with 3’ to 5’ exoribonucleases to adapt RNA pools during some forms of environmental stress. Most recently, he showed that the bacterial Ro60 was tethered by Y RNA to the ring-shaped exonuclease polynucleotide phosphorylase, forming a new bacterial RNA degradation machine. Additionally, he found that bacterial Y RNAs are a new class of tRNA mimics. His discovery of Ro60 and Y RNAs in Salmonella enterica serovar Typhimurium (S. Typhimurium) now allows him to use this genetically tractable human pathogen as a bacterial model. His research is now focused on characterizing the new RNP machine and elucidating the mechanisms by which Ro60 and Y RNAs function in S. Typhimurium.