Rationale
Proteins are the primary active principles within the cell. DNA contains the information necessary to specify the structure and function of proteins, but it does not do so directly: RNA is the intermediary between the two. The necessity for RNA to play this role was recognized by the late 1950's, but a key insight was missing. The difficulty is illustrated by Belozersky & Spirin (1957) and its companion below. The mechanism by which RNA carries information from DNA to protein came as a total surprise.

By the 1960's, the role of messenger RNA (mRNA) as the mediator between inactive DNA and active protein had became clear, part through the work of Brenner et al (1961). The presence or absence of mRNA is the primary means by which the cell controls which proteins are expressed. Much of gene regulation, therefore, boils down to determining the quantity of mRNA under different conditions. The regulation of the lysis/lysogeny decision by phage Lambda is a good case on point. The last article of this section, Belasco et al (1985), addresses one way cells use to match the quantities of mRNA to physiological needs.

Readings and Investigations
    Article: Belozersky AN, Spirin AS (1957).
                    A correlation between the compositions of deoxyribonucleic and ribonucleic acids.
                    Nature 182, 111-112 (1958).
          Companion to Belozersky & Spirin (1957)
          Related article: Crick FHC (1959). The present position of the coding problem.
                    Brookhaven Symp Biol 12:35-39.

    Article: Brenner S, Jacob F, Meselson M (1961).
                    An unstable intermediate carrying information from genes to ribosomes for protein synthesis
                    Nature 190:576-581.
          Companion to Brenner et al (1961)

    Case Study: The lysis/lysogeny decision by phage Lambda
          Gene regulation and bacteriophage
          Related work: Ptashne M (2004). A Genetic Switch, Third Edition. Cold Spring Harbor Press.

    Article: Belasco JG, Beatty JT, Adams CW, von Gabain A, Cohen SN (1985).
                    Differential expression of photosynthesis genes in R. capsulata results from
                    segmental differences in stability within the polycistronic rxcA transcript.
                    Cell (1985) 40:171-181.
          Companion to Belasco et al (1985) Part I and Part II

Things to do and hand in
    8 Nov: Problem Set 7 - mRNA