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Highly purified RNA polymerase from Escherichia coli terminates RNA synthesis in vitro at defined sites on the DNA of coliphage TT. One such site maps at the end of the major ‘early’ transcription region of the genome. A second, distal site is most readily studied in certain mutant strains from which the first site has been deleted. At both sites, termination in vitro is simple (independent of rho or other factors) and both appear to be functional in vivo: We have applied to these sites a technique designed to study base sequences at and beyond RNA termini. The RNA terminated at the first site has cytosine at its 3′ end, and the first base coded by the DNA template beyond the RNA terminus is guanine. The specificity of this sequence is at least 92%. At the second terminator, which is found to be less efficient in its action, the corresponding bases are cytosine and adenine. [ABSTRACT FROM AUTHOR]

Experiments with the non-metabolizable glucose analogue 3-O-methyl-[U-14C]glucose revealed that this substance is transported through lymphocyte membranes by "facilitated diffusion". The uptake process is stimulated immediately upon addition of phytobomagglutinin. Countertransport and saturation experiments indicate that the stimulation provoked by phytohemagglutinin is due to an activation of cartier sites in the membrane. [ABSTRACT FROM AUTHOR]

Sequences in DNA, which act as signals for the termination of transcription, may lie wholly or partially beyond the distal end of the DNA region actually transcribed into RNA. In a hybrid formed between an intact, RNA molecule and its DNA complement, any such untranscribed signal should lie in the region of single-stranded DNA close to the 3′-hydroxyl terminus of the RNA. We show here that hybrids of this type, formed on circular bacteriophage DNA, act as efficient primers for Escherichia coli DNA polymerase I and T4-induced DNA polymerase, under the normal conditions for DNA synthesis in vitro. The DNA product is covalently linked to the 3′-end of the RNA, and co-purifies with it in CsCl equilibrium centrifugation. Priming by RNA is readily detectable even when DNA primers are also present. These and other features of the reaction suggest that it might form the basis of a general method for the study of DNA sequences beyond the termini of RNA chains. [ABSTRACT FROM AUTHOR]

The experimental conditions to study lymphocyte transformation in cultures derived from bovine lymph nodes are described. Both deoxyribonucleoprotein-bound and soluble RNA polymerase can conveniently be tested in cell lysates. During the course of transformation the activities of the two enzymes begin to rise at the same time when the cells begin to accumulate stable RNA. At 30 h after addition of phytohemagglutinin both enzyme activities are enhanced by a factor of two over the controls. [ABSTRACT FROM AUTHOR]