Significant Differences Between Mouse and Human Trophinins Are Revealed by Their Expression Patterns and Targeted Disruption of Mouse Trophinin Gene

• Published in: Biology of reproduction Vol. 66; no. 2; pp. 313 - 321
• Main Authors: NADANO, Daita, SUGIHARA, Kazuhiro, PARIA, Bibhash C, SABURI, Sakura, COPELAND, Neal G, GILBERT, Debra J, JENKINS, Nancy A, NAKAYAMA, Jun, FUKUDA, Michiko N
• Format: Journal Article
• Language: English
• Published: Madison, WI Society for the Study of Reproduction 01.02.2002
• Subjects: Amino Acid Sequence; Animals; Biological and medical sciences; Blastocyst - physiology; Blotting, Southern; Blotting, Western; Cell Adhesion Molecules - biosynthesis; Cell Adhesion Molecules - genetics; Cell Adhesion Molecules - physiology; Chromosome Mapping; Cloning, Molecular; Female; Gene Expression Regulation, Developmental; Genome; Genotype; Humans; Immunohistochemistry; Inbreeding; Mice; Mice, Inbred C57BL; Molecular Sequence Data; Reverse Transcriptase Polymerase Chain Reaction; Species Specificity; X Chromosome - genetics
• DOI: 10.1095/biolreprod66.2.313
• ISSN: 0006-3363

Trophinin has been identified as a membrane protein mediating apical cell adhesion between two human cell lines: trophoblastic HT-H cells, and endometrial epithelial SNG-M cells. Expression patterns of trophinin in humans suggested its involvement in embryo implantation and early placental development. The mouse trophinin gene maps to the distal part of the X chromosome and corresponds to human chromosome Xp11.21–22, the locus where the human trophinin gene maps. Western blot analysis indicates that the molecular weight of mouse trophinin is 110 kDa, which is consistent with the calculated value of 107 kDa. Positive signals for trophinin proteins were detected in preimplantation mouse embryos at the morula and blastocyst stages. Implanting blastocysts do not show detectable levels of trophinin protein, demonstrating that trophinin is not involved in blastocyst adhesion to the uterus in the mouse. Mouse embryo strongly expressed trophinin in the epiblast 1 day after implantation. Trophinin protein was not found in the mouse uteri and placenta after 5.5 days postcoitus (dpc). Targeted disruption of the trophinin gene in the mouse showed a partial embryonic lethality in a 129/SvJ background, but the cause of this lethality remains undetermined. The present study indicates significant differences between mouse and human trophinins in their expression patterns, and it suggests that trophinin is not involved in embryo implantation and placental development in the mouse.