View larger version (84K):
[in a new window]
|
Fig. 1. The germarium, a niche for germline stem cells. (A) A wild-type ovariole
showing the germarium (anterior tip; bracket) and a string of developing egg
chambers, all of which derive from the activity of stem cells in the
germarium. The oocyte is the cell located at the posterior of the cysts that
accumulates most of the green staining. The dashed line labels the anterior
half of the germarium hosting the germline stem cells represented in B and
pictured in C and E. Red: F-actin staining to show the shape and arrangement
of somatic and germline cells. (B) The scheme represents different cell types
present in a wild-type germarium. Terminal filament cells, cap cells and inner
sheath cells are of somatic origin (the dpp gene is expressed in the
cap cells); the differentiating germline cells are the cystoblast (daughter of
a stem cell) and the cystocytes, which form part of 2-, 4-, 8- and 16-cell
cysts. The organelle in red is the fusome, which acquires a spherical shape in
germline stem cells and in cystoblasts in interphase, and a branched
appearance in developing cysts. (C) Wild-type germarium stained with F-actin
to visualise the shape of somatic cells (red); germline cells are stained in
green. The large cells in contact with the cap cells are germline stem cells.
Note the apposition of both cell types. (D) Wild-type germarium showing the
localisation of the Armadillo protein in the junctions between cap cells, and
between the cap cells and the germline stem cells. This focal plane depicts
only three cap cells. (E) Wild-type germarium showing the apical localisation
of the spherical fusome present in germline stem cells. Asterisks label cap
cells.
|
CiteULike 
Complore 
Connotea 
Del.icio.us 
Digg 
Reddit 
Technorati 
Twitter What's this?
