Origination of LTR Retroelement-Derived NYNRIN Coincides with Therian Placental Emergence

Arnon Plianchaisuk, Kazuya Kusama, Kiyoko Kato, Sira Sriswasdi, Kazuhiro Tamura, Wataru Iwasaki

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


The emergence of the placenta is a revolutionary event in the evolution of therian mammals, to which some LTR retroelement-derived genes, such as PEG10, RTL1, and syncytin, are known to contribute. However, therian genomes contain many more LTR retroelement-derived genes that may also have contributed to placental evolution. We conducted large-scale evolutionary genomic and transcriptomic analyses to comprehensively search for LTR retroelement-derived genes whose origination coincided with therian placental emergence and that became consistently expressed in therian placentae. We identified NYNRIN as another Ty3/Gypsy LTR retroelement-derived gene likely to contribute to placental emergence in the therian stem lineage. NYNRIN knockdown inhibited the invasion of HTR8/SVneo invasive-type trophoblasts, whereas the knockdown of its nonretroelement-derived homolog KHNYN did not. Functional enrichment analyses suggested that NYNRIN modulates trophoblast invasion by regulating epithelial-mesenchymal transition and extracellular matrix remodeling and that the ubiquitin-proteasome system is responsible for the functional differences between NYNRIN and KHNYN. These findings extend our knowledge of the roles of LTR retroelement-derived genes in the evolution of therian mammals.

Original languageEnglish
Article numbermsac176
JournalMolecular Biology and Evolution
Issue number9
Publication statusPublished - Sept 1 2022
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Ecology, Evolution, Behavior and Systematics
  • Molecular Biology
  • Genetics


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