NB 5-3 details
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NB 5-3 delaminates at S1 in the intermediate column.
No information about the lineage derived from NB 5-3 is available from other insects.
At S1 NB 5-3 expresses wingless (wg)(Chu-LaGraff et al, 1993; Broadus et al, 1995), intermediate neuroblasts defective (ind) (Weiss et al, 1998), and gooseberry distal (gsb-d) (Doe et al, 1992; Broadus, et al, 1995; Skeath et al, 1995). At S2 it adds seven-up-lacZ (svp-lacZ) expression (Broadus et al, 1995) and at S3, Klumpfuss (Klu) expression (Yang et al, 1997). During S5, it adds unplugged (upg) (Chiang et al, 1995; Broadus et al, 1995) castor (cas) expression (Cui and Doe, 1992, 1995) and runt expression (Doe, 992; Dormand and Brand, 1998).
Bossing et al, (1996) first described the NB 5-3 lineage as consisting of 9-15 interneurons arranged in two clusters. They observed pyknotic cells in the vicinity of this clone and considerable DiI-labled cellular debris, suggesting significant amounts of cell death associated with this clone. Schmidt et al, (1997) amended these observations by reporting a motorneuron in this lineage in addition to the interneurons. We find the clone consists of 5-13 cells, separated into medial and lateral clusters, containing a motoneuron in thoracic segments and a group of interneurons in every segment.
A. Motoneurons
There is at least one motoneuron located laterally in the clone (4.6 um; n=3) in thoracic segments only. It projects ipsilaterally into the posterior root of the ISN, exits the CNS via SNa, and reaches the posterior group of SNa targets, including muscles 23, 24 and 18.
B. Interneurons
There is a medial cluster of three unusually large (6.9 um; n=6) interneurons that cross the posterior commissure and project anteriorly in a lateral fascicle of the connective. A second cluster lies more laterally, and also projects across the posterior commissure (in a more posterior fascicle) before turning anterior in a medial fascicle of the contralateral connective. All of the lateral cells were the same size (4.6 um; n=16).
In abdominal clones, there is also a branch from the lateral cluster that extends into the medial fascicle of the contralateral connective (Fig. 5-3D). All of the cells in the NB 5-3 lineage have large cell bodies and the only projections we observe at stage 17 are intersegmental, but we cannot rule out the possibility that some of these cells are local interneurons.
References:
Bossing, T., Udolph, G., Doe, C. Q., and Technau, G. M. (1996). The Embryonic CNS lineages of Drosophila melanogaster I. Neuroblast lineages derived from the ventral half of the neurectoderm. Dev Biol 179: 41-64.
Broadus, J., Skeath, J. B., Spana, E. P., Bossing, T., Technau, G. M., and Doe, C. Q. (1995). New neuroblast markers and the origin of the aCC/pCC neurons in the Drosophila central nervous system. Mech Dev 53: 393-402.
Chiang, C., Young, K.E., and Beachy, P.A. (1995). Control of Drosophila tracheal branching by the novel homeoomain gene unplugged, a regulatory target for genes of the bithorax complex. Development 121(11):3901-12.
Chu-LaGraff, Q., and Doe, C.Q. (1993). Neuroblast specification and formation regulated by wingless in the Drosophila CNS. Science 261(5128): 1594-7.
Cui, X., and Doe, C.Q. (1992). ming is expressed in neuroblast sublineages and regulates gene expression in the Drosophila central nervous system. Development 116(4): 943-52.
Cui, X., and Doe, C.Q. (1995). The role of the cell cycle and cytokinesis in regulating neuroblast sublineage gene expression in the Drosophila CNS. Development 121(10): 3233-43
Doe, C. Q. (1992). Molecular markers for identified neuroblasts and ganglion mother cells in the Drosophila central nervous system. Development 116: 855-863.
Dormand, E.L., and Brand, A.H. (1998). Runt determines cell fate in the Drosophila embryonic CNS. Development 125(9):1659-67.
Schmidt, H., Rickert, C., Bossing, T., Vef, O., Urban, J., and Technau, G. M. (1997). The embryonic Central Nervous System lineages of Drosophila melanogaster II. Neuroblast lineages derived from the dorsal part of the neurectoderm. Dev Biol 189: 186-204.
Skeath, J. B., Zhang, Y., Holmgren, R., Carroll, S. B., and Doe, C. Q. (1995). Specification of neuroblast identity in the Drosophila embryonic central nervous system by gooseberry-distal. Nature 376: 427-430.
Weiss, J., VonOhlen, T., Mellerick, D., Dressler, G., Doe, C. Q., and Scott, M.P. (1998). Dorsoventral patterning in the Drosophila central nervous system: the intermediate neuroblasts defective homeobox gene specifies intermediate column identity. Genes Dev 12:3591-3602.
Yang, X., Bahri, S., Klein, T., and Chia, W. (1997). Klumpfuss, a putative Drosophila zinc finger transcription factor, acts to differentiate between the identities of two secondary precursor cells within one neuroblast lineage. Genes Dev 11(11):1396-1408.