1 research outputs found
Spatial modelling of transcription dynamics in bacterial gene regulatory networks
Ph. D. Thesis.In Synthetic biology, researchers can alter the DNA sequence of organisms such
that the behaviour to specific inputs is predictable. Regulatory systems have been
‘hacked’ into doing computation, help with bio-production, aid in personalised
medicine and providing highly specific sensors.
A major bottleneck in current synthetic biology is that models fail to predict
system behaviour reliably, causing recent progress to be reliant on the trial and
error of model-assisted system designs.
One of the reasons for the models to fail is the neglect of Spatial effects. While
this neglect simplifies models, recent experimental data shows localised effects.
This work shows that only the combination of 3D cytosol diffusion and the
1D sliding along the chromosome of transcription factors can explain localised
effects; the modelling transcription factors initial sliding route after formation
reproduces experimental results.
However, one essential assumption for the model described above is the initial
location of a functional transcription factor at the encoding gene. While the
coupled transcription and translation in prokaryotes are experimentally verified
and can lead to the localisation of Transcription Factor proteins, this localisation
must be assumed to be transferred to the active dimer form to reproduce the
experiment.
To substantiate this assumption, this work expands the limited field of protein
dimerisation. A new model is introduced to explain the localisation effect with
an extra pathway we call Translation Mediated Dimerisation. Here, the partially
formed transcription factors still undergoing translation are thought to meet and
form a dimer while still constrained to the mRNA on the other end. Even if this
occurs in a minority of events, this can drastically affect non-linear behaviour.
This model allows utilisation of localised effects for the rational design of
system dynamics otherwise unavailable, expanding the possibilities and increasing
the efficiency of synthetic biolog