Transcription factors continued

The enthusiastic search for more and more transcription factors that ensued in the following decade diverted the attention of many molecular biologists from the fundamental problem of how transcription can be initiated or proceed in a chromatin matrix. However, three lines of research continued throughout the 1980s and 1990s that have converged with transcription factor analysis to build the detailed, if still confusing picture we have today. 

Overexpression or deregulated expression of cell cycle-dependent transcription factors such as Myc and Eos may stimulate continued cell division. 

Transcription Factors that Regulate Flavonoid Biosynthetic Genes — continued... 

Cyclin E also performs its function in Gi/S phase. It demonstrates a periodic concentration change with a maximal value at the start of S phase. Afterwards, its concentration falls off sharply within S phase. The gene for cyclin E is also induced by transcription factor E2F which explains the increase in cyclin E at the Gi/S transition. Cyclin E binds and activates CDK2. The activated CDK2 complex is also involved in phosphorylation of the pRb protein. As a consequence, a signal is transmitted, with cooperation of cyclin D, in the direction of the transcription of genes that are essential for the continuation of the cell cycle. 

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-... 

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