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Insulin receptor substrate‐1 is expressed at high levels in all cells of the peri‐implantation mouse embryo
Author(s) -
Puscheck Elizabeth E.,
Pergament Eugene,
Patel Yogesh,
Dreschler Jill,
Rappolee Daniel A.
Publication year - 1998
Publication title -
molecular reproduction and development
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.745
H-Index - 105
eISSN - 1098-2795
pISSN - 1040-452X
DOI - 10.1002/(sici)1098-2795(199804)49:4<386::aid-mrd5>3.0.co;2-j
Subject(s) - biology , endoderm , blastocyst , trophoblast , embryonic stem cell , inner cell mass , endocrinology , medicine , embryo , insulin receptor , microbiology and biotechnology , placenta , insulin , embryogenesis , genetics , insulin resistance , pregnancy , fetus , gene
Insulin and insulinlike growth factors are important for embryonic growth and metabolism. Intracellular transduction for these factors has not been studied in the preimplantation mouse embryo. Peri‐implantation mouse embryos synthesize insulinlike growth factor (IGF)‐II ligand, insulin receptor, IGF‐I receptor, and IGF‐II receptor and respond to IGF‐II, IGF‐I, and insulin metabolically and mitogenically. Maternal tissues in the oviduct and uterus are also sources of IGF‐I and insulin. Signaling of IGFs occurs through insulin receptor substrate (IRS)‐1 and IRS‐2. This paper shows that IRS‐1 mRNA and protein are highly expressed in preimplantation mouse embryos, in embryonic cell lines, and in cultured blastocyst outgrowths. IRS‐1 mRNA and protein are detected in embryo‐derived cell lines cultured to produce the three cell lineages (stem cells, endoderm, and trophoblast cells). IRS‐1 mRNA is detected by reverse transcription‐polymerase chain reaction (RT‐PCR) in the E3.5 blastocyst before implantation and in F9 teratocarcinoma stem cells and parietal endoderm cells. IRS‐1 mRNA is detected by Northern blot hybridization at high levels in stem cells and in differentiated progeny of F9 cells and C3H/NE trophectoderm cells. IRS‐1 protein was detected in these cell lines and in an overexpressing CHO‐IRS‐1 fibroblast cell line by immunocytochemistry. Cultured blastocyst outgrowths are a model for implantation events of the trophoblast/placenta lineage and endoderm/yolk sac lineage. In the blastocyst outgrowth, IRS‐1 protein is detected in inner cell mass cells (ICM cells), primitive endoderm, parietal endoderm, and trophectoderm cells. These data suggest that IRS‐1 is expressed in all cell lineages of the peri‐implantation mouse embryo and mediates some effects of insulin and IGFs at this stage. Mol. Reprod. Dev. 49:386–393, 1998. © 1998 Wiley‐Liss, Inc.