We present a new method for marking single cells and tracing their development through embryogenesis. Cells are labelled with a lipophilic fluorescent tracer (DiI) in their normal positions without impaling their membranes. The dye does not diffuse between cells but is transferred to the progeny, disclosing their morphology in all detail. Behaviour of labelled cells can be observed in vivo (cell divisions, morphogenetic movements and differentiation). Following photoconversion of the dye, fully differentiated clones can be analyzed in permanent preparations. We apply this method for cell lineage analysis of the embryonic Drosophila CNS. Here we describe the fate of the CNS midline cells. We present the complete lineages of these cells in the fully differentiated embryo and show that variability exists in segmental numbers of the midline progenitors as well as in the composition of their lineages.

REFERENCES

Abrams
J. M.
,
White
K.
,
Fessler
L. I.
,
Steller
H.
(
1993
)
Programmed cell death during Drosophila embryogenesis.
Development
117
,
29
43
Bate
C. M.
(
1976
)
Embryogenesis of an insect nervous system. I. A map of the thoracic and abdominal neuroblasts in Locusta migratoria.
J. Embryol. Exp. Morph
35
,
107
123
Bate
C. M.
,
Goodman
C. S.
,
Spitzer
N. C.
(
1981
)
Embryonic development of identified neurons: Segment-specific differences in the H Cell Homologues.
J. Neurosci
1
,
103
106
Bate
C. M.
,
Grunewald
E. B.
(
1981
)
Embryogenesis of an insect nervous system. II: A second class of neuron precursor cells and the origin of the intersegmental connectives.
J. Embryol. Exp. Morph
61
,
317
330
von Bartheld
C. S.
,
Cunningham
D. E.
,
Rubel
E. W.
(
1990
)
Neuronal tracing with DiI: Decalcification, cryosectioning, and photoconversion for light and electron microscopic analysis.
J. Histochem. Cytochem
38
,
725
733
Crews
S. T.
,
Thomas
J. B.
,
Goodman
C. S.
(
1988
)
The Drosophila single minded gene encodes a nuclear protein with sequence similarity to the per gene product.
Cell
52
,
143
151
Doe
C. Q.
(
1992
)
Molecular markers for identified neuroblasts and ganglion mother cells in the Drosophila central nervous system.
Development
116
,
855
863
Doe
C. Q.
,
Technau
G. M.
(
1993
)
Identification and cell lineage of individual neural precursors in the Drosophila CNS.
Trends Neurosci
16
,
510
514
Foe
V.
(
1989
)
Mitotic domains reveal early commitment of cells in Drosophila embryos.
Development
107
,
1
22
Garcia-Bellido
A.
,
Ripoll
P.
,
Morata
G.
(
1973
)
: Developmental compartmentalisation of the wing disc of Drosophila.
Nature
245
,
251
253
Goodman
C. S.
,
Bastiani
M. J.
,
Doe
C. Q.
,
du Lac
S.
,
Helfand
S. L.
,
Kuwada
J. Y.
,
Thomas
J. B.
(
1984
)
Cell recognition during neuronal development.
Science
225
,
1271
1279
Goodman
C. S.
,
Bate
C. M.
,
Spitzer
N. C.
(
1981
)
Embryonic development of identified neurons: Origin and transformation of the H-cell.
J. Neurosci
1
,
94
102
Goodman
C. S.
,
Spitzer
N. C.
(
1979
)
Embryonic development of identified neurons: differentiation from neuroblast to neuron.
Nature
280
,
208
214
Honig
M. G.
,
Hume
R. I.
(
1986
)
Fluorescent carbocyanine dyes allow living neurons of identified origin to be studied in long-term cultures.
J. Cell Biol
103
,
171
187
Jacobs
J. R.
,
Goodman
C. S.
(
1989
)
Embryonic development of axon pathways in the Drosophila CNS. I. A glial scaffold appears before the first growth cones.
J. Neurosci
9
,
2402
2411
Klämbt
C.
(
1993
)
The Drosophila gene pointed encodes two ETS-like proteins which are involved in the development of the midline glial cells.
Development
117
,
163
176
Klämbt
C.
,
Goodman
C. S.
(
1991
)
The diversity and pattern of glia during axon pathway formation in the Drosophila embryo.
Glia
4
,
205
213
Klämbt
C.
,
Jacobs
J. R.
,
Goodman
C. S.
(
1991
)
The midline of the Drosophila central nervous system: a model for the genetic analysis of cell fate, cell migration, and growth cone guidance.
Cell
64
,
801
815
Mitchison
T.
(
1989
)
Polewards microtubule flux in the mitotic spindle: evidence from photoactivation of fluorescence.
J. Cell Biol
109
,
637
652
Nambu
J. R.
,
Franks
R. G.
,
Hu
S.
,
Crews
S. T.
(
1990
)
The single-minded gene of Drosphila is required for the expression of genes important for the development of CNS midline cells.
Cell
63
,
63
75
Nambu
J. R.
,
Lewis
J. O.
,
Wharton
K. A.
Jr.
,
Crews
S. T.
(
1991
)
The Drosophila single-minded gene encodes a helix-loop-helix protein that acts as a master regulator of CNS midline development.
Cell
67
,
1157
1167
Nambu
J. R.
,
Lewis
J. O.
,
Crews
S. T.
(
1993
)
The development and function of the Drosophila CNS midline cells.
Comp. Biochem. Physiol
104
,
399
409
O'Kane
C.
,
Gehring
W. J.
(
1987
)
Detection in situ of genomic regulatory elements in Drosophila.
Proc. natn. Acad. Sci. USA
84
,
9123
9127
Patel
N. H.
,
Schafer
B.
,
Goodman
C. S.
,
Holmgren
R.
(
1989
)
The role of segment polarity genes during Drosophila neurogenesis.
Genes Dev
3
,
890
904
Rothberg
J. M.
,
Jacobs
J. R.
,
Goodman
C. S.
,
Artavanis-Tsakonas
S.
(
1990
)
slit: an extracellular protein necessary for development of midline glia and commissural axon pathways contains both EGF and LRR domains.
Genes Dev
4
,
2169
2187
Schmidt-Ott
U.
,
Technau
G. M.
(
1992
)
Expression of en and wg in the embryonic head and brain of Drosophila indicates a refolded band of seven segment remnants.
Development
116
,
111
125
Sink
H.
,
Whitington
P. M.
(
1991
)
Location and connectivity of abdominal motoneurons in the embryo and larva of Drosophila melanogaster.
J. Neurobiol
12
,
298
311
Stern
C.
(
1936
)
: Somatic crossing over and segregation in Drosophila melanogaster.
Genetics
21
,
625
730
Technau
G. M.
(
1987
)
A single cell approach to problems of cell lineage and commitment during embryogenesis of Drosophila melanogaster.
Development
100
,
1
12
Thomas
J. B.
,
Bastiani
M. J.
,
Bate
C. M.
,
Goodman
C. S.
(
1984
)
From grasshopper to Drosophila: a common plan for neuronal development.
Nature
310
,
203
207
Thompson
K. J.
,
Siegler
M. V. S.
(
1991
)
Anatomy and physiology of spiking local and intersegmental interneurons in the median neuroblast lineage of the grasshopper.
J. Comp. Neurol
305
,
659
675
Thompson
K. J.
,
Siegler
M. V. S.
(
1993
)
Development of segment specificity in identified lineages of the grasshopper CNS.
J. Neurosci
13
,
3309
3318
Udolph
G.
,
Prokop
A.
,
Bossing
T.
,
Technau
G. M.
(
1993
)
A common precursor for glia and neurons in the embryonic CNS of Drosophila gives rise to segment-specific lineage variants.
Development
118
,
765
775
Vincent
J.-P.
,
O'Farell
P. H.
(
1992
)
The state of engrailed expression is not clonally transmitted during early Drosophila development.
Cell
68
,
923
931
Wharton
K. A.
,
Crews
S. T.
(
1993
)
CNS midline enhancers of the Drosophila slit and Toll genes.
Mech. Dev
40
,
141
154
Zalokar
M.
,
Erk
I.
(
1977
)
Phase-partition fixation and staining of Drosophila eggs.
Stain. Technol
52
,
89
95
This content is only available via PDF.