Deposition of H2A.Zub on carp ribosomal cistron and RNA polymerase II promoters. Sequential chromatin immunoprecipitation (ChIP-reChIP) assays showing (A) seasonal enrichment of H2A.Zub along carp ribosomal cistron, and (B) seasonal enrichment of H2A.Zub on the L41 and Δ9-desaturase promoters. (C) Seasonal average ratio (summer/winter) of mRNA levels of ubiquitylation/deubiquitylation factors. The data were normalized with respects to carp 16S mitochondrial rRNA (n = 3 in each season). Standard deviations (± SD) are shown (*P = 0.047, **P = 0.002, ***P = 0.523, Student’s t-test). ChIP-reChIP, sequential chromatin immunoprecipitation; SD, standard deviation.