Following recent discoveries of colocalization of downstream-regulating genes
in living cells, the impact of the spatial distance between such genes on the
kinetics of gene product formation is increasingly recognized. We here show
from analytical and numerical analysis that the distance between a
transcription factor (TF) gene and its target gene drastically affects the
speed and reliability of transcriptional regulation in bacterial cells. For an
explicit model system we develop a general theory for the interactions between
a TF and a transcription unit. The observed variations in regulation efficiency
are linked to the magnitude of the variation of the TF concentration peaks as a
function of the binding site distance from the signal source. Our results
support the role of rapid binding site search for gene colocalization and
emphasize the role of local concentration differences.Comment: 5 pages, 2 figures; Supplementary material contained in the source
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