New twists on H2A.Z: a histone variant with a controversial structural and functional past

Abstract

Integration of histone variants into chromatin organization allows for functional specification of chromatin regions. Recent functional analyses of H2A.Z have ascribed to it a multiplicity of complex and often opposing roles in developmental and homeostatic regulation. However, although the manner in which this essential histone variant is able to mediate its effects is not entirely well understood, current work has sought to investigate its mode of action. It is becoming increasingly clear that H2A.Z does not necessarily act independently, but rather, in conjunction with trans-acting factors to elicit chromatin changes. The nature of these structural changes has remained somewhat controversial but nevertheless exemplifies the seemingly multifaceted nature of H2A.Z.Key words: histone H2A.Z, chromatin structure, transcription, heterochromatin.