Average diffusion constants and mobile fractions of mRNA particles

Range Table - link
Organism Chinese hamster ovary (CHO)
Reference Vargas DY, Raj A, Marras SA, Kramer FR, Tyagi S. Mechanism of mRNA transport in the nucleus. Proc Natl Acad Sci U S A. 2005 Nov 22 102(47):17008-13. doi: 10.1073/pnas.0505580102 p.17012 table 1PubMed ID16284251
Method p.17008 left column bottom paragraph:"[Investigators'] probes are small, hairpin-shaped oligonucleotides called molecular beacons (refs 17, 18) that possess an internally quenched fluorophore whose fluorescence is restored upon hybridization to a specific nucleic acid sequence. To obtain single-molecule sensitivity, [they] engineered a host cell line to express an mRNA possessing multiple molecular beacon binding sites."
Comments p.17012 left column bottom paragraph:"When the temperature was reduced by 12°C, there was a 45% reduction in the average diffusion constant of the particles (Table 1 and Movie 4, which is published as supporting information on the PNAS web site). If the motion of the particles was due to Brownian diffusion, [investigators] would have expected only a 4% reduction because diffusion is directly proportional to absolute temperature when other physical conditions are held constant. A priori, this drop suggests that active processes control the movements of mRNP particles. However, upon ATP depletion, [they] found that the average diffusion constant of the mobile particles was identical to the average diffusion constant measured under physiological conditions (Table 1 and Movie 5, which is published as supporting information on the PNAS web site), suggesting that the motion of the mobile particles is not controlled by enzymatic processes." See note beneath table
Entered by Uri M
ID 111850