Northern blot analysis substantiating the consistency of the cDNA microarray results. Total RNA (10 μg/lane) isolated from HUVEC cultured in the absence or presence of homocysteine for the indicated time periods was analyzed by Northern blot hybridization, followed by autoradiography. (A) Effect of homocysteine on Id-1, NKEFB, clusterin, PAG, SREBP, GADD153, and GADD45 mRNA levels. (B) Effect of homocysteine on GRP78 mRNA levels. Hybridization to a human GAPDH probe was used to normalize RNA loading. The results are representative of 2 separate experiments using 2 different samples of RNA.