Mediator complex subunit Med19 binds directly GATA transcription factors and is required with Med1 for GATA-driven gene regulation in vivo — GATA transcription factors and Mediator complex subunits — Mediator complex subunit Med19 binds directly GATA transcription factors and is required with Med1 for GATA-driven gene regulation in vivo — GATA transcription factors and Med19 mediator complex subunit