The microarray data for the other promoters that are apparently activated by NsrR must be evaluated cautiously , however , because few of these transcripts encode proteins known or suspected to be involved in the response to RNS , and most of the differences were much smaller ( typically two-to threefold apparent activation ) than the 30-fold repression of ytfE , the 14-fold repression of hmpA , and the up-to-15-fold repression of hcp .