Direct vs. synaptic coupling in a mathematical model of cytoneme-based morphogen gradient formation
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Published version
Author(s)
Kim, Hyunjoong
Bressloff, Paul C
Type
Journal Article
Abstract
In developmental biology, an important problem is understanding the mechanisms underlying the formation of morphogen concentration gradients. The most commonly hypothesized mechanism involves the diffusion and degradation of morphogens from a localized source. Recently, however, an alternative mechanism has been proposed, which is based on cell-to-cell contacts mediated by thin, actin-rich cellular extensions known as cytonemes. In this paper, we develop a one-dimensional advection-diffusion transport model of cytoneme-based morphogenesis. In particular, we compare two distinct types of contact between a cytoneme tip and a target cell: direct contact and indirect contact mediated by a synapse. First, we calculate the steady-state concentration profiles and show that synaptic contacts generate broader concentration profiles, thus allowing for longer-range interactions. We then consider two alternative methods for determining how quickly the system approaches steady-state: either calculating the accumulation time using Laplace transforms, or analyzing the discrete spectrum of the associated evolution operator. The latter is a nontrivial eigenvalue problem due to the nature of the boundary conditions. Finally, we extend the direct contact model to the case of a stochastically switching boundary at the cytoneme tip, in order to take into account the fact that cytonemes dynamically grow and shrink, resulting in more temporary contacts with target cells.
Date Issued
2018-01
Date Acceptance
2018-07-05
Citation
SIAM Journal on Applied Mathematics, 2018, 78 (5), pp.2323-2347
ISSN
0036-1399
Publisher
Society for Industrial and Applied Mathematics
Start Page
2323
End Page
2347
Journal / Book Title
SIAM Journal on Applied Mathematics
Volume
78
Issue
5
Copyright Statement
c 2018 Society for Industrial and Applied Mathematics
Identifier
http://dx.doi.org/10.1137/18m1179699
Publication Status
Published
Date Publish Online
2018-09-04