Prior studies have unequivocally established the critical role of intestinal microbiota in colitis pathogenesis, demonstrating that genetically modified mice exhibited altered susceptibility to colitis due to changes in gut microbiota composition.3,27–29 To investigate the functional relationship between the intestinal microbiota and Ring1a deficiency-induced colitis exacerbation in the DSS-induced colitis model, we first co-housed adult Ring1aKO mice with age- and sex-matched WT mice for two weeks and then conducted DSS-induced colitis. Here, RING1 is linked to colitis.