Exploring Six2 distal enhancer interactome in developing mouse kidney

The Six2 distal enhancer regulates expression of the 60 kb-downstream gene Six2, but does not regulate the Six3 gene which is 70 kb further downstream. CTCF ChIP-Seq and Hi-C data points to a chromatin domain boundary between Six2 and Six3 which may intervene interaction between Six2-DE and Six3. The irradiation-induced Brachyrrhine (Br) mutant allele was found to carry a 320 kb genomic inversion that includes Six2 and Six3, but not Six2DE. This repositioned Six2 under Six3 enhancer control and Six3 under Six2 distal enhancer control. Consistent with this, Six3 is ectopically expressed in Br/+ kidneys and Six2 expression is reduced. To test whether there is a change of interaction between Six2 distal enhancer and Six2 or Six3 promoters, we performed 4C-Seq in E16.5 wildtyp or Br/+ mice nephron-genic zone cells. The nephron genic zone cells from E16.5 wildtype or Br/+ kidneys were dissociated following Brown et al., 2015 and subject to 4C-Seq using Dpn II and NlaIII as primary and secondary digest enzyme, with Six2DE as view point.