Controlling {alpha}-globin: a review of {alpha}-globin expression and its impact on {beta}-thalassemia

• Published in: Haematologica (Roma) 2008-12, Vol.93 (12), p.1868-1876
• Main Authors: Voon, Hsiao Phin Joanna, Vadolas, Jim
• Format: Article
• Language: English
• ISSN: 0390-6078; 1592-8721
• DOI: 10.3324/haematol.13490

Cell and Gene Therapy Research Group, The Murdoch Children’s Research Institute, The University of Melbourne, Royal Children’s Hospital, Parkville, Melbourne, Australia Correspondence: Hsiao Phin Joanna Voon, Cell and Gene Therapy Research Group, The Murdoch Children’s Research Institute, The University of Melbourne, Royal Children’s Hospital, Flemington Road, Parkville 3052, Melbourne, Australia. E-mail: joanna.voon{at}mcri.edu.au Synthesis of -globin and -globin subunits of hemoglobin occurs at high levels during erythrocyte differentiation in a tightly controlled and coordinated fashion. Expression of -globin is a fascinatingly complex process which has been meticulously defined in several recent studies, from chromatin modifications to Pol II recruitment. Following this, -globin transcripts are processed and stabilized by a protein complex which binds the 3’ untranslated region. Transcription and stabilization contribute to high level expression of -globin. However, translation of -globin at levels exceeding -globin expression damages cellular membranes and results in β-thalassemia. It is, therefore, crucial that -globin proteins are properly folded and stabilized, processes which are dependent on the presence of haem and AHSP. The exceedingly well-characterized process of -globin expression elegantly illustrates the complex interaction of factors which are required to balance necessary high expression against the negative impacts of overexpression. Key words: hemoglobin, -globin, thalassemia.