G-quadruplexes and mRNA localization

G-quadruplexes represent a novelty for molecular biology. Their role inside the cell remains mysterious. We investigate a possible correlation with mRNA localization. In particular, we hypothesize that G-quadruplexes influence fluid dynamics. Localization of mRNA molecules within the cytoplasm recently emerged as a prevalent mechanism for cell polarization, thus underlying developmental processes. [1] reports 5 adventages for a cell of transporting mRNAs rather than proteins: (i) transport costs are reduced, as several protein molecules can be translated from a single RNA molecule (ii) transporting mRNAs can prevent proteins from acting ectopically (iii) localized translation can facilitate incorporation of proteins into macromolecular complexes [2] (iv) nascent proteins may have properties distinct from pre-existing copies, by virtue of post-translational modifications or through chaperone-aided folding pathways [3] (v) a major advantage of mRNA targeting is that it allows fine-tuning of gene expression in both space and time [4] [5]. Until now three distinct mechanisms have been identified underlying mRNA localization: localized protection from degradation, diffusion-coupled local entrapment and directed transport along a polarized cytoskeleton. But what can control mRNA localization? At the same time the role of fluid dynamics in developmental biology has been acknowledged [6]. Human conception, indeed fertilization in general, takes place in a fluid. Plant roots direct their growth in response to gravity, light, and mechanical stimuli. Local changes in hormone concentration have been shown to be part of the response mechanisms that result in those tropic growth. First of all it is very interesting to note that gravistimulation and mechanical stimulation act on the same transcripts [7]. Furthermore [8] indicates that salt-induced altered gravitropism of root growth is mediated by ion disequilibrium. We know that objects with the same mass do fall at the same speed in the vacuum and hit the ground at the same time, but air resistance hinders this fact. For example, if you drop a tennis ball and a feather at the same time on the Earth, obviously the ball falls faster. In addition we have to consider parasitic drag. Parasitic drag is caused by moving a solid object through a fluid medium (in the case of hydrodynamics, more specifically, a liquid medium). Parasitic drag is made up of many components, the most prominent being form drag. Skin friction and interference drag are also major components of parasitic drag. The shape of the object is the most important factor in form drag or pressure drag: bodies …