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Fig. 4. The permanent precursors of the inner structures are organized into
distinct sectors and are arranged with different orientations after division.
(A) Position of the most distal cell (in µm) in the clones induced at D11.
This position is more distal for clones produced by transient progenitors than
for clones produced by permanent precursors. (B,C,E-G) In toto views of the
matrix. Same clones as in Fig.
2. Arrowheads indicate the cell juxtaposed to the DP. Scale bars:
25 µm. (B,C) IRS clones showing two related pairs of cells (1, 2 and 3, 4)
and progressive intercalation of ß-galactosidase+ cells
between the pairs in layer 3 (see Fig.
6). 1, permanent precursor; 2, transient progenitor; 3,4, cells
originating from division of the progenitor (see text); (D) Diagram of IRS
mode of growth. (E,F) Cuticle clones; (G) A medulla clone. (H) Measurement of
the position (a) of the permanent precursor and of the angle of the alignment
of the permanent precursor and the transient progenitor ( ) with respect
to the proximodistal axis of the DP. (I) position (y-axis, in % of
the length of the proximodistal axis of the DP, `a' value in H) of the
permanent precursors of the IRS (blue lozenge), cuticle (pink square), medulla
(green circle). y-axis is the value (in degrees) of in G of
the IRS (blue cross) and the cuticle (pink cross). x-axis gives the
clone reference (from experiments 1 and 2).
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