Transcriptome Selection Reveals Tumor Genes

Researchers have identified 57 genes linked to the growth of human tumor cells. These genes were pinpointed as a result of transcriptome-scale selection, which was used to isolate genetic suppressor elements (GSEs) inhibiting breast carcinoma cell growth.

The information buried in the genome of an organism is extracted by the process of transcription in which the DNA sequence of a gene is transcribed into the sequence of a messenger RNA (mRNA). The primary steps of this process are mRNA initiation, elongation, and termination. These are coupled to a huge network of post-transcriptional events that mature the mRNA into a form that can be exported from the nucleus to the cytoplasm, where it will be translated into the protein product. The whole process of transcription from initiation to export from the nucleus is highly regulated to ensure the gene products are present only at a specific time or place, for example, at a particular stage of development or in a specific tissue. The corresponding body of transcripts present at any given moment is called the transcriptome.

The strategy employed by investigators at the University of Illinois at Chicago (UIC, USA), described in the July 22, 2003, issue of Cancer Cell, required cutting human DNA into tiny, random fragments; inserting the fragments into a mammalian cell using a vector; and inducing the fragments to express their genetic information. Some of the fragments proved to be biologically active by interfering with the function of the genes from which they were derived.

"Our strategy was validated by the fact that more than half of the genes we identified were already known to play key roles in the growth of cells or the development of cancers,” explained senior author Dr. Igor Roninson, professor of molecular genetics at the University of Illinois. "Many of the other genes, however, were not previously known to be involved in cell division and proliferation. In fact, the functions of some of these genes were entirely unknown. The genes we have identified clearly have the potential to serve as targets for novel therapeutics in the fight against cancer.”



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