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 early on, but the mechanism by which RNA carries information from DNA to protein came as a total surprise.

It soon became clear that the presence or absence of this RNA, now called messenger RNA (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 last article of this section 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)

    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
    13 Nov: Problem Set 9 - mRNA
    20 Nov: Problem Set 10 - Gene regulation