Int. J. Dev. Biol. 52: 887 - 892 (2008)

https://doi.org/10.1387/ijdb.072568om

Vol 52, Issue 7

A histone H1 variant is required for erythrocyte maturation in medaka

Published: 1 September 2008

Osamu Matsuoka¹, Norihisa Shindo², Daisuke Arai¹ and Toru Higashinakagawa*¹

¹Center for Advanced Life and Medical Science, Waseda University, Tokyo, Japan and ²Department of Experimental Pathology, Cancer Institute of the Japanese Foundation for Cancer Research (JFCR), Tokyo, Japan

Abstract

Three histone H1 variants were identified in medaka fish and their sequence characteristics were analyzed. This paper reports one of these variants, termed H1-2, because of its possible implication in erythrocyte maturation. The amino acid sequence of H1-2 was phylogenetically similar to that of other replication-dependent histones. The mRNA transcribed from the h1-2 gene, however, possessed a poly(A) tail without a stem-loop structure, indicating that H1-2 may represent a replication-independent (RI) histone. Transcripts from the h1-2 gene were largely localized in erythrocytes, and knock-down of the h1-2 gene with morpholino antisense oligos resulted in failure to develop mature erythrocytes. In the morphants, residual erythrocytes showed severely impaired nuclear compaction. Although not structurally related to chicken RI histone H5, which is required for erythrocyte maturation, H1-2 may constitute its functional counterpart. Our findings may offer evolutionary insights into the function of H1 variants.

Keywords

replication-dependent histone, replication-independent histone, evolution, medaka