Mrj encodes a DnaJ-related co-chaperone that is essential for murine placental development

Patricia J. Hunter, Bradley J. Swanson, Melissa A. Haendel, Gary E. Lyons, James C. Cross

Research output: Contribution to journalArticlepeer-review

92 Scopus citations

Abstract

We have identified a novel gene in a gene trap screen that encodes a protein related to the DnaJ co-chaperone in E. coli. The gene, named Mrj (mammalian relative of DnaJ) was expressed throughout development in both the embryo and placenta. Within the placenta, expression was particularly high in trophoblast giant cells but moderate levels were also observed in trophoblast cells of the chorion at embryonic day 8.5, and later in the labyrinth which arises from the attachment of the chorion to the allantois (a process called chorioallantoic fusion). Insertion of the ROSAβgeo gene trap vector into the Mrj gene created a null allele. Homozygous Mrj mutants died at mid-gestation due to a failure of chorioallantoic fusion at embryonic day 8.5, which precluded formation of the mature placenta. At embryonic day 8.5, the chorion in mutants was morphologically normal and expressed the cell adhesion molecule α4 integrin that is known to be required for chorioallantoic fusion. However, expression of the chorionic trophoblast-specific transcription factor genes Err2 and Gcm1 was significantly reduced. The mutants showed no abnormal phenotypes in other trophoblast cell types or in the embryo proper. This study indicates a previously unsuspected role for chaperone proteins in placental development and represents the first genetic analysis of DnaJ-related protein function in higher eukaryotes. Based on a survey of EST databases representing different mouse tissues and embryonic stages, there are 40 or more DnaJ-related genes in mammals. In addition to Mrj, at least two of these genes are also expressed in the developing mouse placenta. The specificity of the developmental defect in Mrj mutants suggests that each of these genes may have unique tissue and cellular activities.

Original languageEnglish (US)
Pages (from-to)1247-1258
Number of pages12
JournalDevelopment
Volume126
Issue number6
StatePublished - Mar 1999

Keywords

  • Chaperone
  • Chorioallantoic fusion
  • DnaJ
  • Gene trap screen
  • Mouse
  • Placenta

ASJC Scopus subject areas

  • Molecular Biology
  • Developmental Biology

Fingerprint Dive into the research topics of 'Mrj encodes a DnaJ-related co-chaperone that is essential for murine placental development'. Together they form a unique fingerprint.

Cite this