Histone H5 messenger RNA is polyadenylated

Abstract

In most known systems1,2, histone mRNA lacks the poly(A) sequence at the 3′ end of the molecule typical of most mRNAs. Furthermore, the synthesis of histones, unlike that of most proteins, is tightly coupled to DNA synthesis3–5. Nevertheless, histone synthesis occurs in amphibian oocytes in the absence of DNA synthesis6. Moreover, it has recently been found that in amphibian oocytes most of the histone mRNA is polyadenylated7–9, and the polyadenylate is probably removed during maturation of the oocyte10. Histone H5, an H1-like tissue-specific histone occurring only in nucleated erythrocytes11, is also atypical in that it is synthesised in the absence of DNA synthesis during maturation of the red blood cells12,13. We report here that H5 mRNA is polyadenylated.