RESUMEN
Sonic hedgehog (SHH) is a master developmental regulator. In 1995, the SHH crystal structure predicted that SHH-E176 (human)/E177 (mouse) regulates signaling through a Zn2+-dependent mechanism. While Zn2+ is known to be required for SHH protein stability, a regulatory role for SHH-E176 or Zn2+ has not been described. Here, we show that SHH-E176/177 modulates Zn2+-dependent cross-linking in vitro and is required for endogenous signaling, in vivo. While ectopically expressed SHH-E176A is highly active, mice expressing SHH-E177A at endogenous sites (ShhE177A/-) are morphologically indistinguishable from mice lacking SHH (Shh-/-), with patterning defects in both embryonic spinal cord and forebrain. SHH-E177A distribution along the embryonic spinal cord ventricle is unaltered, suggesting that E177 does not control long-range transport. While SHH-E177A association with cilia basal bodies increases in embryonic ventral spinal cord, diffusely distributed SHH-E177A is not detected. Together, these results reveal a novel role for E177-Zn2+ in regulating SHH signaling that may involve critical, cilia basal-body localized changes in cross-linking and/or conformation.
Asunto(s)
Proteínas Hedgehog/química , Proteínas Hedgehog/metabolismo , Transducción de Señal , Zinc/química , Animales , Anticuerpos/química , Anticuerpos/metabolismo , Especificidad de Anticuerpos/inmunología , Cuerpos Basales/efectos de los fármacos , Cuerpos Basales/metabolismo , Secuencia de Bases , Cilios/efectos de los fármacos , Cilios/metabolismo , Reactivos de Enlaces Cruzados/metabolismo , Embrión de Mamíferos/efectos de los fármacos , Embrión de Mamíferos/metabolismo , Humanos , Ratones , Prosencéfalo/efectos de los fármacos , Prosencéfalo/enzimología , Prosencéfalo/metabolismo , Conformación Proteica , Multimerización de Proteína/efectos de los fármacos , Transducción de Señal/efectos de los fármacos , Médula Espinal/efectos de los fármacos , Médula Espinal/embriología , Médula Espinal/metabolismo , Zinc/farmacologíaRESUMEN
Group 2 innate lymphoid cells (ILC2s) are a subset of ILCs that play a protective role in the response to helminth infection, but they also contribute to allergic lung inflammation. Here, we report that the deletion of the ETS1 transcription factor in lymphoid cells resulted in a loss of ILC2s in the bone marrow and lymph nodes and that ETS1 promotes the fitness of the common progenitor of all ILCs. ETS1-deficient ILC2 progenitors failed to up-regulate messenger RNA for the E protein transcription factor inhibitor ID2, a critical factor for ILCs, and these cells were unable to expand in cytokine-driven in vitro cultures. In vivo, ETS1 was required for the IL-33-induced accumulation of lung ILC2s and for the production of the T helper type 2 cytokines IL-5 and IL-13. IL-25 also failed to elicit an expansion of inflammatory ILC2s when these cells lacked ETS1. Our data reveal ETS1 as a critical regulator of ILC2 expansion and cytokine production and implicate ETS1 in the regulation of Id2 at the inception of ILC2 development.
