designed for use with sample purified from mouse cells any of the following two primer pairs are preferred written in the conventional 5 u2032 to 3 u2032 orientation for arrays designed for use with sample purified from rat cells the following primer pair is preferred written in the conventional 5 u2032 to 3 u2032 orientation in addition to the above controls several wells of the microtiter plate may contain pcr primer pairs that are specific for mrnas that are present in essentially all human cells and which code for proteins or enzymes that provide what are commonly referred to as housekeeping functions hkg these primer pairs provide confirmation that preparation of the mrna achieved a required yield and that integrity of the mrna was maintained during preparation most preferably these control wells are placed in the same row as the aforementioned controls primer pairs suitable for amplifying mrnas coding for the above housekeeping genes include the following primer pairs that amplify the following human mouse and rat mrnas designated by the name of the protein they encode and in parentheses their corresponding gene symbols shown all primer sequences are listed in the 5 u2032 to 3 u2032 orientation the 12 wells available in a.