Non-classical transcriptional regulation of HLA-G: an update

Philippe Moreau1, Sébastien Flajollet, Edgardo D Carosella

  • 1Commissariat à l'Energie Atomique, Direction des Sciences du Vivant, I2BM, Service de Recherches en Hémato-Immunologie, Institut Universitaire d'Hématologie, Hôpital Saint-Louis, Paris, France. philippe.moreau@cea.fr

Human leucocyte antigen-G (HLA-G) plays a key role in maternal-foetal tolerance and allotransplantation acceptance and is also implicated in tumour escape from the immune system. The modulation of HLA-G expression can prove to be very important to therapeutic goals in some pregnancy complications, transplantation, cancer and possibly autoimmune diseases. In spite of substantial similarities with classical HLA-class I genes, HLA-G is characterized by a restricted tissue-specific expression in non-pathological situations. HLA-G expression is mainly controlled at the transcriptional level by a unique gene promoter when compared with classical HLA-class I genes, and at the post-transcriptional level including alternative splicing, mRNA stability, translation and protein transport to the cell surface. We focus on the characteristics of the HLA-G gene promoter and the factors which are involved in HLA-G transcriptional modulation. They take part in epigenetic mechanisms that control key functions of the HLA-G gene in the regulation of immune tolerance.

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