Eukaryotics, gene regulation

All steps—from changes in DNA template, sequence, and accessibility in chromatin to RNA stability—are subject to modulation and hence are potential control sites for eukaryotic gene regulation. 

C. Eukaryotic gene regulation is much more complex than in prokaryotes, with expression dependent on several types of transcription factors as well as chromatin structure. 

Spencer, C.A. and Groudine, M. (1990) Transcription elongation and eukaryotic gene regulation. Oncogene, 5, 777-785. 

The elucidation of the structure of the nucleosome core particle—a large protein-DNA complex— facilitates the description in Chapter 31 of key processes in eukaryotic gene regulation. 

We have seen how interactions between DNA-binding proteins such as CAP and RNA polymerase can activate transcription in prokaryotic cells (Section 31.1.6). Such protein-protein interactions play a dominant role in eukaryotic gene regulation. In contrast with those of prokaryotic transcription, few eukaryotic transcription factors have any effect on transcription on their own. Instead, each factor recruits other proteins to build up large complexes that interact with the transcriptional machinery to activate or repress Panscription. 

Eukaryotic gene regulation begins with an activated transcription factor bound to a specific site on DNA. One scheme for the initiation of transcription by RNA polymerase II requires five steps ... 

In fact, the term "promoter architecture" has been coined to illustrate this point. As discussed in Chapter 29, selective eukaryotic gene regulation is the result of cell-specific promoter architectures. 

In highly developed eukaryotes gene regulation is expressed during differentiation (9), hormonally influenced processes (10) and the control of cellular phenotype, which are the most complex cell functions, and an involvement of ADP-ribosyl transferase is documented. 

In contrast to the termination of transcription in prokaryotes which takes place precisely at the 3 end of the mRNA, that of eukaryotes occurs usually beyond the normal 3 end of mRNA. The 3 ends of nonhistone eukaryotic mRNAs are generated by an endonucleolytic cleavage with accompanying addition of a poly(A) tail (see Section II, this chapter). This suggests that the termination of eukaryotic transcription involves mechanisms different from those of prokaryotic transcription. Furthermore, the mechanism of termination is presumed to play a role in eukaryotic gene regulation (98). 

---