--- emacsbug.el~	2013-02-11 22:45:54.714731000 +0000
+++ emacsbug.el	2013-04-11 00:37:32.109258200 +0000
@@ -162,7 +162,12 @@
     (setq message-end-point
 	  (with-current-buffer (get-buffer-create "*Messages*")
 	    (point-max-marker)))
-    (compose-mail report-emacs-bug-address topic)
+    (if (eq mail-user-agent 'gnus-user-agent)
+	(progn
+	  (require 'gnus) ;; It defines `gnus-newsgroup-name'.
+	  (let ((gnus-newsgroup-name "report-emacs-bug"))
+	    (compose-mail report-emacs-bug-address topic)))
+      (compose-mail report-emacs-bug-address topic))
     ;; The rest of this does not execute if the user was asked to
     ;; confirm and said no.
     (when (eq major-mode 'message-mode)