Two mRNA species encoding the differentiation-associated histone H1(0) are produced by alternative polyadenylation in mouse.

Histone H1(0) is a differentiation-specific member of the histone H1 family. The accumulation of the protein is associated with the terminal stage of cell differentiation and is regulated at various levels. In mouse, the analysis of the expression of the single copy gene encoding H1(0) has shown that another H1(0)-related mRNA species (0.9 kb) is present in addition to the usual 2.1-kb mRNA. In this study, we have cloned and sequenced the smaller H1(0)-related mRNA. This mRNA seems to be produced by the use of an additional polyadenylation signal present in the 3' untranslated region (UTR) of the initial transcript. This smaller H1(0)-encoding mRNA is expressed only in mouse and is transferred into polysomes as efficiently as the larger version upon the induction of cell differentiation. The use of the described polyadenylation site removes over 1 kb of the 3' UTR of H1(0) mRNA and seems to be involved in the regulation of H1(0) mRNA stability.