Systems factor-response elements

Logically, if a response has an effect on some other system, then it must be a factor of that other system. It is not at all unusual for variables to have this dual identity as response and factor. In fact, most systems are seen to have a rather complicated internal subsystem structure in which there are a number of such factor-response elements (see Figure 1.4). The essence of responses as factors is illustrated in the drawings of Rube Goldberg (1930) in which an initial cause triggers a series of intermediate factor-response elements until the final result is achieved. 

Transcription factors are DNA binding proteins that interact with specific DNA sequences, called response elements, located in the regulatory or promoter regions of genes. In bacterial systems, these response elements are called operator sites. 

The third basic element of general system theory is the transform. As we have seen, it is the link between the factors and the responses of a system, transforming levels of the system s factors into levels of the system s responses. 

The transcription factor cAMP response element-binding protein (CREB) is considered to be involved in the regulation of specific phases of adult neurogenesis in the SVZ/olfactory bulb system (Giachino et al., 2005) and in the SGZ for hippocampal neurons (Bender et al., 2001 Nakagawa et al., 2002). 

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