Abstract
Stochastic fluctuations (or "noise") in the single-cell populations of molecular
species are shaped by the structure and biokinetic rates of the underlying gene
circuit. The structure of the noise is summarized by its autocorrelation function. In
this paper, we introduce the noise regulatory vector as a generalized framework for
making inferences concerning the structure and biokinetic rates of a gene circuit
from its noise autocorrelation function. While most previous studies have focused
primarily on the magnitude component of the noise (given by the zero-lag
autocorrelation function), our approach also considers the correlation component,
which encodes additional information concerning the circuit. Theoretical analyses
and simulations of various gene circuits show that the noise regulatory vector is
characteristic of the composition of the circuit. While a particular noise regulatory
vector does not map uniquely to a single underlying circuit, it does suggest possible
candidate circuits, while excluding others, thereby demonstrating the probative
value of noise in gene circuit analysis.