Gene networks

Gene network is a group of genes functioning in a coordinated manner to con trol vital processes in an organism. Each gene network includes several ess ential components: (1) a group of genes which form a core of a gene network , (2) proteins encoded by these genes, (3) signal transduction pathways, (4 ) negative and positive feedback which provide for autoregulation, and (5) low-molecular-weight compounds. To accumulate the information on gene netwo rks, a database GeneNet has been developed (http://wwwmgs.bionet.nsc.ru/sys tems/mgl/genenet/). At present, GeneNet contains the data on 16 gene networ ks which are arranged in six sections according to the subject concerned: l ipid metabolism, steroidogenesis, erythropoiesis, antiviral response, plant seed development, and heat shock. Analysis of these data revealed the foll owing principles of the gene network organization: (1) there is a great var iety of molecular mechanisms which provide for a feedback regulation; (2) e ach gene network includes key genes which coordinate the function of the ot her genes of the gene network; (3) one transcription factor activates many genes via a cassette mechanism; and (4) gene networks are autoregulated via regulatory circuits with positive and negative feedback.