Project description:Sp8 and Sp6, members of the Sp family of transcription factors, are required in a dose-dependent manner to induce Fgf8 and En1 in the limb bud ectoderm, therefore controlling proximo-distal and dorso-ventral limb development. Mouse genetics revealed that Sp8 makes a much greater contribution than Sp6 but the nature of its regulatory mechanism was unknown. Here, by combining ChIP-seq and RNA-seq genome-wide analyses we show that Sp8 predominantly functions as an activator from putative distal enhancers regulating crucial limb patterning genes and underscoring its master role in limb development. We also provide compelling evidence for Sp8 cooperating with Dlx5 for the regulation of a considerable set of its target genes. Our work supports a model in which Sp8, Sp6 and Dlx5 act conjointly to regulate target genes with a final functional outcome that depends on their relative availability. This should be considered when interpreting Sp and Dlx mutant phenotypes.
Project description:Sp8 and Sp6, members of the Sp family of transcription factors, are required in a dose-dependent manner to induce Fgf8 and En1 in the limb bud ectoderm, therefore controlling proximo-distal and dorso-ventral limb development. Mouse genetics revealed that Sp8 makes a much greater contribution than Sp6 but the nature of its regulatory mechanism was unknown. Here, by combining ChIP-seq and RNA-seq genome-wide analyses we show that Sp8 predominantly functions as an activator from putative distal enhancers regulating crucial limb patterning genes and underscoring its master role in limb development. We also provide compelling evidence for Sp8 cooperating with Dlx5 for the regulation of a considerable set of its target genes. Our work supports a model in which Sp8, Sp6 and Dlx5 act conjointly to regulate target genes with a final functional outcome that depends on their relative availability. This should be considered when interpreting Sp and Dlx mutant phenotypes.
Project description:Sp8 and Sp6 are two closely related Sp genes expressed in the limb ectoderm, where they regulate proximo-distal and dorso-ventral patterning. Genetic studies in mice have shown that they act in a dose-dependent manner, with Sp8 exerting a substantially stronger effect than Sp6. Here, we integrate ChIPmentation-seq and RNA-seq analyses to elucidate their genome-wide regulatory networks and mechanisms of action. Our results show that Sp8 has a dual mode of action either directly binding GC-rich motifs or indirectly binding AT-rich motifs through Dlx. In contrast, Sp6 primarily acts through AT-rich motifs, likely via interaction with cofactors such as Dlx5. Both factors regulate key components of the Wnt, FGF, and BMP signaling pathways, central to limb patterning, and display both cooperative and independent roles. We further show that Sp8 and Sp6 can form homo- and heterodimers, as well as interact with Dlx5, revealing a complex regulatory network. Our findings provide molecular insight into limb morphogenesis and have potential implications for understanding congenital limb malformations.
Project description:Sp8 and Sp6 are two closely related Sp genes expressed in the limb ectoderm, where they regulate proximo-distal and dorso-ventral patterning. Genetic studies in mice have shown that they act in a dose-dependent manner, with Sp8 exerting a substantially stronger effect than Sp6. Here, we integrate ChIPmentation-seq and RNA-seq analyses to elucidate their genome-wide regulatory networks and mechanisms of action. Our results show that Sp8 has a dual mode of action either directly binding GC-rich motifs or indirectly binding AT-rich motifs through Dlx. In contrast, Sp6 primarily acts through AT-rich motifs, likely via interaction with cofactors such as Dlx5. Both factors regulate key components of the Wnt, FGF, and BMP signaling pathways, central to limb patterning, and display both cooperative and independent roles. We further show that Sp8 and Sp6 can form homo- and heterodimers, as well as interact with Dlx5, revealing a complex regulatory network. Our findings provide molecular insight into limb morphogenesis and have potential implications for understanding congenital limb malformations.
