Differential actions of fibroblast growth factors on intracellular pathways and target gene expression in bovine ovarian granulosa cells. Jiang Z et al. Several fibroblast growth factors (FGFs) alter ovarian granulosa cell function, including FGF1, FGF4 and FGF10. These ligands exhibit different patterns of receptor activation, and their mechanisms of action on granulosa cells remain unknown. The objective of the present study was to identify the major pathways and target genes activated by FGF1, FGF4 and FGF10 in primary oestrogenic granulosa cells cultured under serum-free conditions. FGF1 and FGF4 increased levels of mRNA encoding Sprouty family members, SPRY2 and SPRY4, and the orphan nuclear receptors NR4A1 and NR4A3. Both FGF1 and FGF4 decreased levels of mRNA encoding SPRY3 and the pro-apoptotic factor BAX. FGF1 but not FGF4 stimulated expression of the cell cycle regulator, GADD45B. In contrast, FGF10 altered the expression of none of these genes. Western blot demonstrated that FGF4 activated ERK1/2 and Akt signalling rapidly and transiently, whereas FGF10 elicited a modest and delayed activation of ERK1/2. These data show that FGF1 and FGF4 activate typical FGF signalling pathways in granulosa cells, whereas FGF10 activates atypical pathways.
Ovarian localization
Oocyte
Comment
Cloning and Characterization of the SSB-1 and SSB-4 Genes Expressed in Zebrafish Gonads. Li JZ et al. The protein of the gustavus (gus) gene has a typical SOCS box domain and repeats in the splA and RyR (SPRY) domains. GUS can interact with Vasa and is necessary for the specification of germ cells. We cloned two zebrafish genes, SSB-1 and SSB-4 (SPRY domain SOCS box proteins). Phylogenetic analysis shows that zebrafish SSB-1 and SSB-4 are clustered into clades of SSB-1-like and SSB-4-like genes from other species. RT-PCR analysis of tissues revealed that zebrafish SSB-1 and -4 are expressed in the ovary and testis. We investigated the spatial expression patterns of zebrafish SSB-1 and -4 in embryos from the two-cell stage to 72 h postfertilization (hpf) using whole-mount in situ hybridization. SSB-1 and -4 transcripts were present in all blastomeres during the early embryonic stages, but the genes differ in their expression pattern. SSB-4 mRNA was located in the region of the primordial germ cells in 24 and 72 hpf embryos, but SSB-1 mRNA was not detected at these stages. We hypothesize that SSB-4 plays a role in the early development of germ cells.