FGF Ligand Family mRNA Expression Profile for Mouse Preimplantation Embryos, Early Gestation Human Placenta, and Mouse Trophoblast Stem Cells

Abstract

Signaling by fibroblast growth factor (FGF) is essential is for trophoblast stem (TS) cells and preimplantation embryos. FGF4 provides essential signaling, but the expression of the complete set of 23 FGF family members has not been analyzed. Here, semi-quantitative RT-PCR and microarray analyses were used to define expression of all FGF ligand mRNA. RT-PCR was done for developmentally important FGF subfamilies, FGF10/FGF22 and FGF8/FGF17/FGF18 as well as FGF11. FGF4 and FGF18 are detected at highest levels by RT-PCR and microarrays. FGF10 was detected at low levels in both assays. FGF11 was detected at moderate levels by microarray, but not by RT-PCR. FGF17 was detected at low levels by array and moderate levels by RT-PCR. FGF8 and FGF22 were detected by RT-PCR, but not by microarrays during late cleavage divisions. FGF8, FGF5, and FGF9 were detected in the oocyte by microarray. FGF2, FGF3, and FGF7 were not detected by RT-PCR or microarrays and FGF13, FGF14, and FGF23 were not detected by microarray. Since a major role of FGF is to maintain TS cells, we tested human and mouse placental cell lines and early gestation human placenta for expression of FGF ligands. Expression in mouse TS cells was compared with preimplantation embryos, and human placental cell line expression was compared with human placenta, to infer which ligands are expressed in placental lineage vs. other cell lineages. The data suggest that human and mouse placenta share FGF18 and its high expression suggests preimplantation and early placental function.

Regulation and action of fibroblast growth factor 17 in bovine follicles

“…In the female reproductive system, FGF17 mRNA has been described only in isolated mouse oocytes and embryos (Zhong et al 2006). In the present study, we describe FGF17 mRNA predominantly in oocytes, compared with lower expression in granulosa and theca cells.…”

“…Very little is known about the pattern of expression of FGF17 in the reproductive system. mRNA encoding FGF17 was detected in human prostatic epithelial cells (Polnaszek et al 2004), human placenta, and in mouse oocytes and embryos (Zhong et al 2006).…”

Ectopic expression of Fgf3 leads to aberrant lineage segregation in the mouse parthenote preimplantation embryos

“…In this study, we found elevated Fgfr2 signaling in parthenotes starting from the 16-cell morula stage, as indicated by increased Fgfr2 phosphorylation, in spite of unchanged Fgf4 expression in parthenotes. We found that Fgf3 expression was undetectable or expressed at a low-to-moderate level in normal mouse preimplantation embryos (Rappolee et al, 1988(Rappolee et al, , 1994Zhong et al, 2006), but was strongly expressed in parthenote embryos. Our finding that inhibition of Fgfr2 suppressed Gata4 but not Fgf3 expression in parthenotes (Supp.…”

Mechanisms of fibroblast growth factor signaling in the ovarian follicle

“…Messenger RNA encoding FGF3 and FGF22 has been detected in mouse oocytes (Zhong et al 2006), although any potential action on follicular cells has not been reported.…”

“…Messenger RNA encoding all three genes has been detected in mouse oocytes; in a microarray study, Fgf8 and Fgf18 were highly expressed in mouse oocytes whereas Fgf17 was weakly expressed (Zhong et al 2006). Although Fgf8 mRNA was initially reported to be located exclusively in oocytes in the adult female mouse (Valve et al 1997), another study reported transcripts in theca and granulosa cells in cattle (Schmitt et al 1996, Zammit et al 2002, Buratini et al 2005.…”