Operon model

See Monod (1971) this work also provides accessible and interesting accounts of the allostery and operon models. 

The operon model and the concept of messenger RNA, first proposed in the Proceedings of the French Academy of Sciences in 1960, are presented in this historic paper. 

Repression and induction. Immediately adjacent to the promoter is the operator (O), which is a binding site for a repressor (R). When the operator is free, transcription is initiated and proceeds through the operator region and on to the genes coding for the three proteins. On the other hand, if the repressor is bound to the operator, transcription is blocked. When the operon model was first proposed, the chemical nature of the repressor was unknown. However,... 

It was Jacob and Monod in 1961 who proposed the operon model for the regulation of transcription. The lac operon is a good example of how operons work (Fig. 1). The operon model proposes three elements ... 

The operon model was described in 1961 by F. Jacob and J. Monod to account for the molecular and genetic mechanisms involved in bacterial enzyme indue-... 

Figure 13.1 Operon model for control of protein synthesis. The example chosen is the lactose (lac) operon. I, regulatory gene p, promoter site o, operator gene z, y, and a represent the structural genes for j8-galactosidase, permease, and transacetylase, respectively.

Z3. Zuckerkandl, E., Controller. ne diseases. The operon model applied to /3-thalassemia, familial fetal hemoglobinemia and the normal switch from the production of fetal hemoglobin to that of adult hemoglobin. J. Mol. Biol. 8, 128-147 (1964). 

Cys2Hisi zinc-finger domain (p. 895) P-galactosida.se (p. 896) operon model (p. 897) repressor (p. 897)... 

Figure 26.2 The operon model, as proposed in 1961 by Jacob and Monod. 

As the work of Ozbudak et al. and Vilar, Guet and Leibler on the lac operon demonstrated, abstract kinetic models with a few variables are sometimes sufficient to capture the essential behavior of the system, e.g., the bistable switch in the lac operon. Some arbitrariness may seem to exist in how these simple lac operon models were generated, because they seem to look very different and the dynamical variables are not the same. However,... 

A number of publications have appeared on the dynamics of enzyme synthesis in a variety of situations. Most of the models are based on more or less sophisticated versions of the operon model of Jacob and Monod. The role of m-RNA and its stability were modeled by Terui (1972). Repressor and inducer control was treated by Knorre (1968), Imanaka et al. (1972 1973), van Dedem and Moo-Young (1973), and Suga et al. (1975). Allowance for dual control and catabolite repression was made by Toda (1976). [See also the kinetic treatment by Yagil and Yagil (1971), Imanaka and Aiba (1977), and Bajpai and Ghose (1978)]. A simple structured model was developed by Roels (1978) showing a combination of the features of the models published. More recently Toda (1981) reviewed the effects of induction and repression of enzymes in microbial cultures and their modeling. 

The operon model was developed by Jacob and Monod, and it has only been demonstrated in prokar-yotie systems. It is the basis for the explanation of Enzyme induction (see) and Enzyme repression (see). See also Attenuation. 

If his4 is an operon, then kis4A, B, and C regions must specify three polypeptides which aggregate to form the final multifunctional product. A difficulty with the operon model is the complete polarity of his4A nonsense mutants. Some complementation between his4A nonsense mutants and other his4 mutants should have been observed. Alterna-... 

The chronological list of major events in lac operon studies below gives a perspective to the reader. This chronology can be separated into two major phases first, the period culminating in the proposal of the operon model in 1961 second, the period from 1961 to the present, in which the concept of the operon guided research. 

F. Jacob and J, Monod [9]. Operon model of control proposed. 

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