Primary gene activity

There are two other examples for the recraitment of genes from primary metabolism. The homospermidine synthase from Senecio vernalis is derived from deoxyh T3usine synthase, an enzyme required for activation of translation factor 5A, and a serine carboxypeptidase-like protein that functions as an acyltransferase in secondary metabolism has been found in Arabidopsis thaliana. 

Primary physiological function Regulates osmotic pressure and pH Multifunctional transporter Relevant in biocompatibility and drug delivery Blood clotting Relevant in biocompatibility and drug delivery Defense mechanism Transport Hormone with intensive effects on metabolism Binding and compaction of DNA in the chromatin. Gene activation... 

The level of detailed knowledge is much higher for certain repressor proteins and their interactions with DNA. The structures of four polypeptides that specifically bind to DNA have been determined recently, namely the lac repressor protein,< - > the cro repressor protein from bacteriophage, the catabolite gene activator protein from Escheria coli, and the amino-terminal fragment of the Cl repressor protein from bacteriophage In addition to the primary structure of the polypeptide, the sequence of the base pairs in that DNA fragment to which the relatively short polypeptide is bound, is known. Furthermore, structural data about the conformation of the peptide backbone are available, e.g., strands of a-helices followed by antiparallel -pleated sheets. 

Fig. 58. Models for control of gene activity during primary embryonic induction. (After Tiedemann, 1967)...

We must still define some of the terms we will be using. Gene activity can be classified into primary and secondary processes. Under primary... 

Thus, differential gene activity is also demonstrable at the level of the proteins. One can depart still further from primary gene activity and consider the formation of visible characters. Character formation proceeds in an orderly sequence, first the development of character A, then that of character B, etc. According to our general concept differential gene activity should lie behind this visible sequence of events. Experimental evidence for this was obtained in a number of cases using antimetabolities of... 

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