This study describes the use of microarray-based expression monitoring to analyze the expression of 1000 human genes. The researchers used DNA microarrays containing 1046 human cDNAs to quantitatively monitor the differential expression of human genes in response to heat shock and phorbol ester treatments in human T cells. The microarrays were printed with high-speed robotics and used in a two-color fluorescence hybridization assay to detect changes in gene expression. The arrays were then sequenced to identify the genes responsible for the observed expression changes. The study identified several known and novel heat shock and phorbol ester-regulated genes in human T cells, demonstrating the sensitivity of the microarray-based approach. The results showed that 17 array elements displayed altered fluorescence ratios of ≥2.0-fold, with 11 genes induced by heat shock and 6 showing modest repression. Sequencing of these genes revealed that 14 of the 17 clones matched known sequences, while three did not. These included a novel gene (B7) that showed significant homology to an EST from Caenorhabditis elegans. The study also examined the effects of phorbol ester treatment on gene expression, identifying six array elements that showed ≥2.0-fold elevated signals. Sequencing of these genes revealed that five matched known sequences, while one did not. The most highly induced genes were the PAC-1 tyrosine phosphatase and nuclear factor-kappa B1 (NF-κB1). The study further demonstrated the ability of microarrays to monitor gene expression in human tissues, showing that all 15 heat shock and phorbol ester-regulated genes were detectable in four tissue types. The expression levels of these genes in Jurkat cells correlated closely with their expression in the four tissues. The study highlights the potential of microarrays for large-scale gene discovery and expression analysis. The high sensitivity and specificity of the microarray-based approach allow for the identification of novel genes and the characterization of gene expression patterns in response to various stimuli. The results demonstrate the utility of microarrays in understanding the molecular mechanisms underlying cellular responses to environmental and physiological changes. The study also emphasizes the importance of continued research into microarray technology for improving the resolution and accuracy of gene expression analysis.This study describes the use of microarray-based expression monitoring to analyze the expression of 1000 human genes. The researchers used DNA microarrays containing 1046 human cDNAs to quantitatively monitor the differential expression of human genes in response to heat shock and phorbol ester treatments in human T cells. The microarrays were printed with high-speed robotics and used in a two-color fluorescence hybridization assay to detect changes in gene expression. The arrays were then sequenced to identify the genes responsible for the observed expression changes. The study identified several known and novel heat shock and phorbol ester-regulated genes in human T cells, demonstrating the sensitivity of the microarray-based approach. The results showed that 17 array elements displayed altered fluorescence ratios of ≥2.0-fold, with 11 genes induced by heat shock and 6 showing modest repression. Sequencing of these genes revealed that 14 of the 17 clones matched known sequences, while three did not. These included a novel gene (B7) that showed significant homology to an EST from Caenorhabditis elegans. The study also examined the effects of phorbol ester treatment on gene expression, identifying six array elements that showed ≥2.0-fold elevated signals. Sequencing of these genes revealed that five matched known sequences, while one did not. The most highly induced genes were the PAC-1 tyrosine phosphatase and nuclear factor-kappa B1 (NF-κB1). The study further demonstrated the ability of microarrays to monitor gene expression in human tissues, showing that all 15 heat shock and phorbol ester-regulated genes were detectable in four tissue types. The expression levels of these genes in Jurkat cells correlated closely with their expression in the four tissues. The study highlights the potential of microarrays for large-scale gene discovery and expression analysis. The high sensitivity and specificity of the microarray-based approach allow for the identification of novel genes and the characterization of gene expression patterns in response to various stimuli. The results demonstrate the utility of microarrays in understanding the molecular mechanisms underlying cellular responses to environmental and physiological changes. The study also emphasizes the importance of continued research into microarray technology for improving the resolution and accuracy of gene expression analysis.