The Haspin gene: location in an intron of the Integrin alpha E gene, associated transcription of an Integrin alpha E-derived RNA and expression in diploid as well as haploid cells

Haspin is a serine/threonine kinase, recently identified in mice, that is t hought to regulate cell cycle and differentiation of haploid germ cells. He re, the haspin gene is identified within an intron of the integrin alphaE g ene. Transcription occurs from a bi-directional CpG island-associated promo ter that also generates an alternatively spliced integrin alphaE derived RN A. Remarkably, the human and murine haspin genes lack introns, and have fea tures of retroposons. The human haspin cDNA reveals that the human and muri ne proteins are 83% identical in the C-terminal kinase domain, but only 53% identical in the N-terminal region. The haspin kinase domain has structura l features that distinguish it from previously characterized proteins and s uggest that haspin is a member of a new family of protein kinases. Although formerly thought to be expressed selectively in the testes, haspin is also transcribed at lower levels in thymus, bone marrow, fetal liver and other fetal tissues, and in all proliferating cell lines tested. Thus haspin is l ikely to be important in regulation of diploid as well as haploid cell diff erentiation in a variety of tissues. (C) 2001 Elsevier Science B.V. All rig hts reserved.