Transcription factors gene activation

Genes for transcription factors that activate growth-promoting genes ... 

A considerable number of transcription factors have reactive cysteine residues, which enable them to respond to the redox conditions in the cell. Since cadmium perturbs redox homeostasis, it can affect this class of transcription factors. If cadmium can displace the tetra-coordinate zinc atoms in zinc finger-containing transcription factors, it will affect them as well. Many of the pathways involving activation and inactivation of transcription factors involve kinases and phosphatases, themselves under the intricate control of calcium fluxes. It is therefore no surprise that cadmium will exert effects on the activity of transcription factors, the activation of proto-oncogenes, and thereby on gene expression (Figure 20.8i and i ). 

Important substrates in Gi/S phase are the transcription factor E2P, the tumor suppressor protein pRb and pRb-related proteins. E2P represents a family of heterodimeric transcription factors with activity strictly regulated in the cell cycle. The members of the E2P family regulate transcription of genes with products that are required for the... 

Datta, R., Taneja, N., Sukhatme, V.P., Qreshi, S.A., Weichselbaum. R. Kufe, D.W. (1993) Reactive oxygen intermediates target CC(Amediate activation of early growth response transcription factor gene by ionising radiation. Proc. natl Acad. Sci. USA, 90, 2419-2422... 

Promoters for class II genes contain consensus sequences, such as the TATA or Hogness box, the CAAT box, and the GC box. They serve as binding sites for proteins called general transcription factors, which, in turn, interact with each other and with RNA polymerase II. Enhancers are DNA sequences that increase the rate of initiation of transcription by binding to specific transcription factors called activators. 

Transcriptional activators. Many proteins serve as activators of transcription, causing larger increases in rate over those observed with TBP alone. Some of these are listed in Table 28-2.338a The table also lists two proteins (Spl and NF1), and the DNA sequence CCAAT, which control constitutive or continuously active genes. A large group of transcription factors are active in development. Receptors may be resident in cytoplasm, cell membrane or nucleus, as indicated in Table 28-2. Some cytoplasmic factors are latent, becorn-... 

VAN DER FITS, L., MEMELINK, J., The jasmonate-inducible AP2/ERF-domain transcription factor ORCA3 activates gene expression via interaction with a jasmonate-responsive promoter element. Plant J., 2001,25,43-53. 

The levels of particular enzymes (and indeed of specific proteins in general) is determined by the balance of protein degradation versus the specific expression of the protein (through the process of specific gene transcription, translation and post-translational processing of the protein). Genes can either be constitutively expressed (in which case they are normally always being transcribed) or are inducible, that is, specific transcription factors are activated... 

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