sentence: Concentrated and purified virions digested with subtilisin , were lysed and then subjected to immunoblot analysis using the following antibodies : monoclonal α - IN ( a kind gift of Dag Helland and Alan Engelman ) ; affinity purified polyclonal α - INI1 , INI1-PB3 ( Yung et al ., 2001 ) ; goat polyclonal α - p24 , monoclonal α - gp41 , polyclonal α - p30 , polyclonal α - VSV ( were provided by Dr. Ott ) ; polyclonal α - BRG1 , α - BAF155 , α - BAF170 ( gift of Dr. Weidong Wang at National Institute on Aging , National Institute of Health ) .