Index: wp-includes/formatting.php
===================================================================
--- wp-includes/formatting.php	(revision 18315)
+++ wp-includes/formatting.php	(working copy)
@@ -1003,7 +1003,7 @@
 	$tagqueue = '';
 	$newtext = '';
 	$single_tags = array('br', 'hr', 'img', 'input'); // Known single-entity/self-closing tags
-	$nestable_tags = array('blockquote', 'div', 'span'); // Tags that can be immediately nested within themselves
+	$nestable_tags = array('blockquote', 'div', 'span', 'q'); // Tags that can be immediately nested within themselves
 
 	// WP bug fix for comments - in case you REALLY meant to type '< !--'
 	$text = str_replace('< !--', '<    !--', $text);