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Riddle DL, Blumenthal T, Meyer BJ, et al., editors. C. elegans II. 2nd edition. Cold Spring Harbor (NY): Cold Spring Harbor Laboratory Press; 1997.

Cover of C. elegans II

C. elegans II. 2nd edition.

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Section IVSomatic Gonad

Ablation of somatic gonad cells with a laser microbeam has been used to investigate the role of these cells in germ-line development. Ablation of the DTC(s) at any time during larval development and in the adult results in all germ cells entering the meiotic pathway (Kimble and White 1981). By ablating certain somatic gonad cells, the DTC can be mispositioned. When this occurs, germ cells adjacent to the DTC proliferate, whereas those at a distance enter meiosis. These experiments demonstrate that the DTC promotes proliferation (or inhibits entry into the meiotic pathway) locally, and its position at the end of the gonad arm helps to establish the distal-proximal germ-line polarity.

Ablation of the DTC (hermaphrodite) or the linker cell (male) indicates that these cells control the reflexed shape of the gonad arms (Kimble and White 1981). The U-shaped gonad is not crucial for normal germ-line development: Mutations that alter the migratory behavior of the DTC or linker cell, and thus change the shape of the gonad arm (Hedgecock et al. 1987; see Antebi et al., this volume), display essentially normal germ-line development.

Sterile mutations in a number of genes seem to affect primarily the somatic gonad. These include gon-2 , where Z1 and Z4 fail to divide (E. Lambie, pers. comm.); gon-4 , which displays early lineage defects, and gon-1 , which displays later lineage defects (S. Santa Anna-Arriola et al., pers. comm.); mig-5 (C. Guo and E. Hedgecock, pers. comm.); and gon(q7) (J. Bork and J. Kimble, pers. comm.), which may be defective in specification of the DTC fate; and shv mutants, where abnormal lineages give rise to ectopic DTCs (and gonad arms) (R. Francis et al., unpubl.). Genetic and molecular characterizations of these and other genes affecting the somatic gonad are in their early stages.

Copyright © 1997, Cold Spring Harbor Laboratory Press.
Bookshelf ID: NBK20198

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