Characterisation of major histocompatibility complex class I genes at the fetal-maternal interface of marsupials

Immunogenetics. 2015 Jul;67(7):385-93. doi: 10.1007/s00251-015-0842-5. Epub 2015 May 9.


Major histocompatibility complex class I molecules (MHC-I) are expressed at the cell surface and are responsible for the presentation of self and non-self antigen repertoires to the immune system. Eutherian mammals express both classical and non-classical MHC-I molecules in the placenta, the latter of which are thought to modulate the maternal immune response during pregnancy. Marsupials last shared a common ancestor with eutherian mammals such as humans and mice over 160 million years ago. Since, like eutherians, they have an intra-uterine development dependent on a placenta, albeit a short-lived and less invasive one, they provide an opportunity to investigate the evolution of MHC-I expression at the fetal-maternal interface. We have characterised MHC-I mRNA expression in reproductive tissues of the tammar wallaby (Macropus eugenii) from the time of placental attachment to day 25 of the 26.5 day pregnancy. Putative classical MHC-I genes were expressed in the choriovitelline placenta, fetus, and gravid endometrium throughout the whole of this period. The MHC-I classical sequences were phylogenetically most similar to the Maeu-UC (50/100 clones) and Maeu-UA genes (7/100 clones). Expression of three non-classical MHC-I genes (Maeu-UD, Maeu-UK and Maeu-UM) were also present in placental samples. The results suggest that expression of classical and non-classical MHC-I genes in extant marsupial and eutherian mammals may have been necessary for the evolution of the ancestral therian placenta and survival of the mammalian fetus at the maternal-fetal interface.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Base Sequence
  • Evolution, Molecular
  • Female
  • Genes, MHC Class I / genetics*
  • Histocompatibility Antigens Class I / genetics*
  • Histocompatibility Antigens Class I / immunology*
  • Macropodidae / genetics
  • Macropodidae / immunology*
  • Membrane Proteins / genetics
  • Membrane Proteins / immunology
  • Phylogeny
  • Placenta / immunology*
  • Pregnancy
  • RNA, Messenger / biosynthesis
  • Sequence Analysis, DNA


  • Histocompatibility Antigens Class I
  • Membrane Proteins
  • RNA, Messenger