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. Author manuscript; available in PMC: 2016 Jul 1.
Published in final edited form as: Biol Trace Elem Res. 2015 Apr 21;166(1):72–81. doi: 10.1007/s12011-015-0296-5

Figure 4. Arsenic-induced depletion of SLBP and subsequent aberrant polyadenylation of H3.1 mRNA and its effects.

Figure 4

Arsenic exposure induces depletion of the stem-loop binding protein (SLBP) by affecting both its protein and mRNA levels. Arsenic epigenetically silences the SLBP gene reducing SLBP mRNA levels and enhances SLBP’s proteasomal degradation. The loss of SLBP prevents it from binding to the stem-loop structure on H3.1 mRNA and the mRNA acquires a poly(A) tail via a downstream poly(A) signal sequence.. The poly(A) tail provides the H3.1 mRNA with increased stability and translation, which allow for presence of H3.1 mRNA outside of S-phase and increased H3.1 levels. Increased polyadenylated H3.1 mRNA may disrupt nucleosome assembly and interfere with H3.3 deposition, which can influence gene expression and facilitate carcinogenesis.