Tob1 expression in normal and osteoarthritic cartilage (oligonucleotide array experiments). (a) Area of one customized SensiChip microarray illustrating the 70-mer oligonucleotide spots that represent the 3'-untranslated region of human Tob1 and demonstrate its differential expression between normal and one late-stage osteoarthritic cartilage. (b) Trend plot demonstrating the transcriptional downregulation of human Tob1 in all RNA samples from cartilage of late-stage osteoarthritis patients used for SensiChip hybridization experiments. The logarithmic ratio of differential Tob1 expression calculated by the software Resolver is plotted against the corresponding osteoarthritic patient sample used for expression profiling. Error bars indicate standard deviations of ratios. P values for the ratios of all 10 osteoarthritic samples were less than 0.05. (c) Transcriptional downregulation of human Tob1 in late-stage osteoarthritic cartilage samples from 10 human donors. All Tob1 ratios were calculated by the gene expression analysis software Resolver. P values for the ratios of all 10 osteoarthritic samples were less than 0.05. (d) Plot of average Tob1 signal intensities from independent SensiChip microarray hybridizations using RNA samples from normal cartilage, late-stage osteoarthritic cartilage and cultured primary human chondrocytes. Tob1 signal intensities from independent SensiChip hybridizations of RNA samples from pooled normal cartilage (10 hybridization experiments), 10 late-stage osteoarthritis patients (10 hybridization experiments) and 5 different cell culture samples of proliferating primary human chondrocytes (5 hybridization experiments) were merged respectively and are plotted as average Tob1 signal intensities. Error bars indicate standard deviations of Tob1 signal intensities.