Na+-dependent medium-affinity uptake of L-glutamate in the insect epidermis

The possibility that communication through gap junctions may be important during embryonic development has often been raised since gap junctions were first described between early embryonic cells. It is now known that this direct cell-to-cell communication pathway disappears between groups of embryonic cells with different developmental fates as the embryo progresses through development, suggesting that transfer through the gap junctional pathway may play some part in controlling events during development. Supportive evidence for a role for gap junctions comes from experiments demonstrating that the properties of gap junctions differ at the border separating each segment in insect epidermis. Recently it has been shown that the ability to exchange small dyes between cells in the amphibian embryo depends on the position of each cell with respect to the grey crescent. When communication through gap junctions is prevented, by injecting antibodies to gap junctions protein, pattern formation is severely disturbed in the non-communicating region. The paper describes experiments on the pattern of junctional communication at early stages of development of the amphibian embryo and illustrates how anti-gap junction antibodies are being used to determine when and where communication through gap junctions may play an important role during development.

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Hypotheses for gradient mechanisms in insect epidermis

The Science of Nature ◽

10.1007/bf00623009 ◽

1966 ◽

Vol 53 (19) ◽

pp. 510-510 ◽

Cited By ~ 3

Author(s):

Michael Locke

Keyword(s):

Insect Epidermis

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Permeability of gap junctions at the segmental border in insect epidermis

Cell ◽

10.1016/0092-8674(82)90342-7 ◽

1982 ◽

Vol 28 (2) ◽

pp. 243-252 ◽

Cited By ~ 97

Author(s):

Anne E. Warner ◽

Peter A. Lawrence

Keyword(s):

Gap Junctions ◽

Insect Epidermis

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A model for the genetic control of differential adhesion in insect epidermis

Journal of Theoretical Biology ◽

10.1016/0022-5193(79)90086-9 ◽

1979 ◽

Vol 81 (1) ◽

pp. 129-149 ◽

Cited By ~ 3

Author(s):

Jay E. Mittenthal

Keyword(s):

Genetic Control ◽

Differential Adhesion ◽

Insect Epidermis

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Proteins constituting insect epidermis.

Hikaku seiri seikagaku(Comparative Physiology and Biochemistry) ◽

10.3330/hikakuseiriseika.10.12 ◽

1993 ◽

Vol 10 (1) ◽

pp. 12-18

Author(s):

Susumu IZUMI

Keyword(s):

Insect Epidermis

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Insect epidermis: polarity patterns after grafting result from divergent cell adhesions between host and graft tissue

Development ◽

10.1242/dev.110.4.1071 ◽

1990 ◽

Vol 110 (4) ◽

pp. 1071-1079

Author(s):

K. Nubler-Jung ◽

B. Mardini

Keyword(s):

Cell Sheet ◽

Intermediate Stage ◽

Epidermal Cells ◽

Host Cells ◽

Planar Polarity ◽

Differentiated Cells ◽

Local Sequence ◽

Two Factors ◽

Insect Epidermis ◽

Graft Tissue

Insect epidermal cells display planar polarity (i.e. polarity in the plane of the cell sheet) by secreting oriented cuticular denticles and bristles before each moult. We investigate how cell polarities in an abdominal segment are uniformly oriented towards the posterior of the animal. Recently we have shown for the cotton bug Dysdercus that, in 180 degrees-rotated grafts pretreated with colchicine, graft cells tend to adopt the orientation prevailing in surrounding host cells via an intermediate stage with outward oriented denticles (Nubler-Jung and Grau, 1987). Here we show that, in untreated grafts that were transposed along the anteroposterior segment axis, the denticles also always tend to point outwards. This independence of the polarity pattern from the direction of transposition is compatible neither with a gradient model for polarity control, nor with the assumption that epidermal cells orient according to the local sequence of distinctly differentiated cells. Instead we found that outward orientation of graft denticles correlates with an elongation of epidermal cells along a host-graft border with divergent cell adhesiveness. We therefore propose that outward orientation in a graft results from a combination of two factors: epidermal cells stretch along an interface with divergent cell adhesiveness, and they form a denticle perpendicular to their long axis. By analogy, the normal anteroposterior orientation of denticles in a segment may result because epidermal cells tend to elongate parallel to the segment boundary and to form denticles perpendicular to this mediolateral cell elongation, i.e. along the anteroposterior segment axis.

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