Differential gene activation

While the use of reiterated DNA/RNA hybridization is an appealing tool to study differential gene activity in developing systems, it is clear that the experiments must be carefully controlled and sound interpretations await further studies on the biological importance of the reiterated sequences. 

Amino Acids. — Alkaloids. — Porphyrins. — Cell Division. — Differential Gene Activity as Principle of Differentiation. — Regulation. — Polarity and Unequal Cell Division as Fundamentals of Differentiation. — Cell Elongation. 

The cellular level implies the whole complex of processes which are determined by differential gene activity and consist of a system of organospecific syntheses. The latter determines the cell differentiation. 

The chapters of this book are dedicated to the analysis of the system of interactions determined by differential gene activity on different levels... 

The Expression of Differential Gene Activity in Transcriptional Level... 

In this way the different phases of embryogenesis are characterized by the synthesis of different, stage-specific mRNA molecules, which reflect the differential gene activity at the time. 

However, the development of mosaic eggs does not differ principally from the development of eggs of the regulatory type. The development of the mollusk Ilyanassa is also characterized by spatial and temporal differential gene activity and a well-expressed periodicity in morphogenetic nuclear activity. The sequence of transcription in the development of the different tissues of Ilyanassa is given in Table 1. 

Puffing as a Cytological Indicator of Differential Gene Activity... 

One peculiar expression of differential gene activity is termed gene amplification. This phenomenon has the effect of causing those parts of DNA which should synthesize a large amount of RNA to be repeatedly copied or amplified. 

Speculations on the more commonplace role of amplification in the genetic control of cell differentiation are also in doubt. In these speculations, the assumption is made that extra copies of rDNA could be a crucial factor in determination and control of differential gene activity during ontogenesis (Brown and Dawid, 1969). However, at this time there is no serious basis for this kind of wide generalization. 

Apparently amplification is only particular and unusual mechanism for realization of differential gene activity and possibly occurs only for those genes represented in the genome as polycopies. 

The Realization of Differential Gene Activity on the Post-Transcriptional, Translational, and Post-Translational Levels... 

The Realization of Differential Gene Activity synthetase cistron... 

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