title: An extended steepness model for leg-size determination based on Dachsous/Fat trans-dimer system.
abstract: What determines organ size has been a long-standing biological question. Lawrence et al. (2008) proposed the steepness hypothesis suggesting that the protocadherin Dachsous/Fat (Ds/Ft) system may provide some measure of dimension to the cells in relation to the gradient. In this paper we extended the model as a means of interpreting experimental results in cricket leg regeneration. We assumed that (1) Ds/Ft trans-heterodimers or trans-homodimers are redistributed during cell division, and (2) growth would cease when a differential of the dimer across each cell decreases to a certain threshold. We applied our model to simulate the results obtained by leg regeneration experiments in a cricket model. The results were qualitatively consistent with the experimental data obtained for cricket legs by RNA interference methodology. Using our extended steepness model, we provided a molecular-based explanation for leg size determination even in intercalary regeneration and for organ size determination.
authors.affiliation: Faculty of Mathematics, Kyushu University, Motooka 744, Nishi-ku, Fukuoka, 819-0395, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yoshida
authors.affiliation: Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata-cho, Kita-ku, Okayama city, Okayama, 700-8530, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Bando
authors.affiliation: Department of Life Systems, Institute of Technology and Science, The University of Tokushima, Jyosanjima-cho, Tokushima City, 770-8506, Japan.
authors.forename: Taro
authors.initials: T
authors.lastname: Mito
authors.affiliation: Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, 2-5-1 Shikata-cho, Kita-ku, Okayama city, Okayama, 700-8530, Japan.
authors.forename: Hideyo
authors.initials: H
authors.lastname: Ohuchi
authors.affiliation: Department of Life Systems, Institute of Technology and Science, The University of Tokushima, Jyosanjima-cho, Tokushima City, 770-8506, Japan.
authors.forename: Sumihare
authors.initials: S
authors.lastname: Noji
mesh_terms: D000818:Animals; D015820:Cadherins / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism; D002452:Cell Count; D002455:Cell Division; D016764:Cell Polarity; D049109:Cell Proliferation; D005121:Extremities / Q000293:injuries / Q000502:physiology*; D005786:Gene Expression Regulation; D006135:Gryllidae / Q000166:cytology* / Q000502:physiology; D015233:Models, Statistical; D009929:Organ Size; D055503:Protein Multimerization; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D012038:Regeneration; D015398:Signal Transduction
chemical_list: D015820:Cadherins; D034741:RNA, Small Interfering