4 



Ribonucleic Acid and the 

 Control of Cellular Processes 



Marko Zalokar ^ 



Introduction 



Several recent reviews deal with the production of RNA - and its 

 function in protein synthesis ( Brachet, 1957; Chantrenne, 1958; Rob- 

 erts et at, 1959; Simkin, 1959; Woods, 1959). They demonstrate the 

 important role that RNA plavs in cell metabolism. A direct experi- 

 mental approach to the prol)lem of RNA control of cellular processes 

 has seldom been made and anv discussion of it will have to be based 

 on few facts and many assumptions. 



Our knowledge of cell physiology has advanced enormously in 

 recent years and most important has been the recognition of the role 

 of nucleic acids in hereditv. The concept of DNA as the chemical 

 basis of genes emerged from many experimental facts. The concept 

 found its main support in the demonstration that DNA is the active 

 principle in bacterial transformations (Avery et ah, 1944; Hotchkiss, 

 1951; Ephrussi-Taylor, 1951), that in bacteriophage, DNA serves in 

 the production of new phage particles in the bacterial host ( Hershey 

 and Chase, 1952; Hershev, 1953), and that in higher organisms the 

 DNA content of cell nuclei is constant and proportional to ploidy 

 (Boivin and the Venderlys, 1948; Mirsky and Ris, 1949). A model 



^ Department of Microbiology, Yale Uni\ersity, New Ha\en, Connecticut. This 

 work was supported by a grant from the National Institutes of Health, United States 

 Public Health Service. Present address; Department of Biology, Uuixcrsity of Cali- 

 fornia at San Diego, La Jolla, California. 



-The following abbre\ iations are used: RNA, ribonucleic acid; DNA, deo.xy- 

 ribonucleic acid. 



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