Assembly of the &lt;i&gt;Mycobacterium tuberculosis&lt;/i&gt; type VII ESX-1 secretion system in &lt;i&gt;Mycobacterium smegmatis&lt;/i&gt; identifies a new transcriptional activator of &lt;i&gt;esx-1&lt;/i&gt; genes and a novel TB vaccine. The gene discussed is ESX1; the disease is tuberculosis.