Figure 2

cDNA array analysis of mammary tumors and osteopontin gene expression. (a) The section of the Atlas™ Mouse 1.2 Array (Clontech, Chatsworth, CA) showing the differential expression of several genes in mammary fat pads transplanted with TM6-HOG and fed with 0.1 and 3 ppm Se in their diet. B2h, mSim transcription factor; B7i, YB1 DNA-binding protein; B12f, prothymosin α ; B13b, osteopontin (OPN); C2j, apolipoprotein E; G11, ubiquitin (housekeeping gene for normalization). (b) Representative hybridization of reverse transcription–polymerase chain reaction (RT–PCR) bands from mammary fat pads of mice transplanted with TM6-HOG and fed with 0.1 and 3 ppm Se in their diet that were probed with an OPN probe followed by a β-actin probe. The expression of OPN was 14-fold higher in the TM6 tumor than in TM6-HOG (left panel) and was decreased 3.85-fold by the high selenium diet (right panel). The actin levels were similar, indicating equivalent input for RNA in the assay. The negative controls for the RT–PCR were reactions without reverse transcriptase (–RT) during first-strand synthesis of cDNA.