Figure 2

Functional categories of genes represented on the HG-U133A GeneChip ¹⁷⁴ and expressed by ARPE-19 cells. A total 130 functional categories are displayed on the abscissa. These are arranged alphabetically in groups under 15 large functional subheadings indicated on the right and separated by dashed lines. The numbers of genes represented and expressed were converted into percentages indicated on the ordinate. The formulae used for calculating percentages were different for each color-coded bar. Yellow bar = total number of genes expressed by ARPE-19 within the functional category/total number of genes expressed in all categories. The heights of the yellow bars may reflect the relative importance of a given function in ARPE-19 cells. Red bar = total number of genes expressed within the functional category/total number of genes represented on the HG-U133A GeneChip¹⁷⁴ in all categories. Blue bar = total number of genes represented within the functional category/total number of genes represented in all categories. Comparisons of the heights of the red versus blue bars in each category show considerable variation from the overall average of approximately 33% expressed. Based on a z-test analysis, categories that have statistically higher-than-predicted percentages expressed are noted by "+;" those with statistically lower-than-predicted percentages expressed are noted by "-." These differences indicate that the functional profile of genes expressed are not a simple reflection of the functional profile of genes represented on the chip. Abbreviations: Ca – calcium; BDNF – brain derived neurotrophic factor ; IGF – insulin growth factor; TRH – thyroid releasing hormone; GABA – gamma amino butyric acid; NADPH – nicotinamide adenine dinucleotide phosphate (reduced form); 5HT – 5 hydroxytryptamine; AMPA – alpha amino-3-hydroxy-5-methylisoxazole-4-proprionic acid; NMDA – n-methyl-d-aspartate.