Pharmacoproteomics is a rapidly advancing field in which the techniques of proteomics are applied to develop pharmaceutical agents it is the study of proteomes, a proteome being the full complement of proteins expressed by an organism or tissue under specified conditions at a specified time.
Over the last several years, the genomes of more than a hundred organisms have been sequenced, and more are being completed each month. Genomics has provided DNA sequences for a tremendous number of bacteria, viruses, and yeasts, as well as humans and a number of model higher organisms (eg, worm, fly, fish, mouse, rat, etc). This DNA sequence information provides the foundation for Functional Genomics. This multidisciplinary field, described in detail below, utilizes various measures of mRNA and protein expression and function to better understand the basis of metabolism and disease processes.
Transcriptomics, a branch of Functional Genomics, is an approach that enables the analysis of gene expression through the detection and relative quantitation of individual messenger RNAs (mRNAs). By comparing transcription profiles of untreated vs treated or normal vs diseased cells or organisms, much can be learned about the biology of the system being studied. Transcriptomic methods usually are based on some type of microarray technology (eg, cDNA or oligonucleotide arrays). Using these methods, quantitative information can be obtained quickly on thousands or tens of thousands of transcripts at a time. Bioinformatic approaches are being developed in an attempt to make sense of this mountain of information, deriving pathway maps and inferring protein function. This, in turn, provides new insight into the gene products associated with cellular processes and disease.
Transcriptomics, though only a few years old, is already providing very useful information about mRNA expression. Ultimately, however, it is not mRNA that regulates and mediates cellular function. Instead, function is directed by the proteins translated from these mRNAs. Studies comparing mRNA and protein levels typically have shown a weak or poor correlation between them.