A fundamental question in brain development is how precursor cells generate a diverse group of neural progeny in an ordered manner. Drosophila neuroblasts sequentially express the transcription factors Hunchback (Hb), Krüppel (Kr), Pdm1/Pdm2 (Pdm) and Castor (Cas). Hb is necessary and sufficient to specify early-born temporal identity and, thus, Hb downregulation is essential for specification ...

The Drosophila tracheal system, a tubular network, is formed from isolated ectodermal metameres by guided branch outgrowth and branch fusion. Branch outgrowth is triggered by the localized and transient activity of Branchless (Bnl/dFGF). Here, we report the discovery of a mesodermal cell that links the leading cells of outgrowing main branches 2.5 hr before they fuse. This bridge-cell serves as...

Insects such as Drosophila melanogaster undergo a derived form of segmentation termed long germband segmentation. In long germband insects, all of the body regions are specified by the blastoderm stage. Thus, the entire body plan is proportionally represented on the blastoderm. This is in contrast to short and intermediate germband insects where only the most anterior body regions are specified...

Congenital vertebral malformations (CVM) pose a significant health problem because they can be associated with spinal deformities, such as congenital scoliosis and kyphosis, in addition to various syndromes and other congenital malformations. Additional information remains to be learned regarding the natural history of congenital scoliosis and related health problems. Although significant progr...

The etiology of congenital scoliosis and its development remains unclear and has not yet been fully identified, even there are theories that congenital scoliosis could be derived from the failure of formation or failure of segmentation, which are etiologically heterogeneous with genetic, epigenetic, and environmental factors contributing to their occurrence. We reported a case of long-term foll...

STUDY DESIGN A retrospective case series of patients with myelomeningocele (MMC) who underwent kyphectomy and posterior segmental fixation using Luque rods and 16-gauge wires. OBJECTIVE To assess outcomes after posterior kyphectomy and segmental fixation for kyphosis in patients with MMC. METHODS Thirteen consecutive patients who underwent posterior kyphectomy for transforaminal fixation co...

Neural precursors often generate distinct cell types in a specific order, but the intrinsic or extrinsic cues regulating the timing of cell fate specification are poorly understood. Here we show that Drosophila neural precursors (neuroblasts) sequentially express the transcription factors Hunchback --> Krüppel --> Pdm --> Castor, with differentiated progeny maintaining the transcription factor ...

The pair-rule gene even-skipped is required for the initiation of metameric pattern in Drosophila. But Drosophila segmentation is evolutionarily derived and is not representative of most insects. Therefore, in order to shed light on the evolution of insect segmentation, homologs of the pair-rule gene even-skipped have been studied in several insect taxa. However, most of these studies have repo...

Anteroposterior polarity of the Drosophila embryo is initiated by the localized activities of the maternal genes, bicoid and nanos, which establish a gradient of the hunchback (hb) morphogen. nanos determines the distribution of the maternal Hb protein by regulating its translation. To identify further components of this pathway we isolated suppressors of nanos. In the absence of nanos high lev...

The subdivision of the anterior-posterior axis in Drosophila is achieved by a cascade of spatially regulated transcription factors which form short-range gradients at the syncytial blastoderm stage. These factors are assumed to have concentration-dependent regulatory effects on their target genes. However, there is so far little direct in vivo evidence that a single factor can autonomously acti...