What is the dorsal-ventral axis?
What is the dorsal-ventral axis?
The dorsal/ventral axis is defined by a line that runs orthogonal to both the anterior/posterior and left/right axes. The dorsal end is defined by the upper or back side of an organism. The ventral end is defined by the lower or front side of an organism.
What does dorsal do in Drosophila?
The dorsal {dl) protein is a member of the Rel family of transcription factors. It is distributed in a nuclear concentration gradient along the dorsoventral axis of Drosophila embryos and activates or represses a discrete set of zygotic genes in a concentration-dependent manner.
Which gene helps establish the anterior-posterior axis in a Drosophila embryo?
The Gap genes: Gap genes participate in early patterning along the anterior-posterior axis of Drosophila embryos. These zygotically transcribed genes, including hunchback, Krüppel, knirps and giant, are expressed in specific spatial domains within 2 hours AEL, just before the cellular blastoderm stage.
Where in the embryo is dorsal expressed?
zen is expressed in the dorsal half of the embryo as early as nc 11, and builds in time until mid-to-late nc 14, when its expression pattern refines into a narrow stripe (Figure 4E), presumably from Dpp signaling (Rushlow et al., 2001).
How dorsal-ventral side of Drosophila is determined at molecular level?
Dorsal-ventral polarity is established by the gradient of a transcription factor called Dorsal. After its translocation, the Dorsal protein acts on cell nuclei to specify the different regions of the embryo. Different concentrations of Dorsal protein in the nuclei appear to specify different fates in those cells.
Which gene is formed dorsal axis in amphibians?
β-catenin is necessary for forming the dorsal axis, since experimental depletion of β-catenin transcripts with antisense oligonucleotides results in the lack of dorsal structures (Heasman et al. 1994a).
How dorsal ventral side of Drosophila is determined at molecular level?
Is dorsal a transcription factor?
Dorsal (DL) is the focal protein in the development of dorsoventral polarity in the developing fly. It is a transcription factor, activating and repressing zygotic genes responsible for differentiation along the dorsoventral axis during the early stages of development.
How was anterior-posterior axis formed in Drosophila?
Three independent genetic pathways interact to form the anterior-posterior axis of the Drosophila embryo. In each case, the initial asymmetry is established during oogenesis, and the pattern is organized by maternal proteins soon after fertilization.
How dorsal and ventral pattern is initially established in Drosophila development?
Dorsal-ventral polarity is established by the gradient of a transcription factor called Dorsal. Unlike Bicoid, whose gradient is established within a syncytium, Dorsal forms a gradient over a field of cells that is established as a consequence of cell-to-cell signaling events.
How is the dorsal-ventral axis formation in amphibians?
If eggs are rotated toward the end of the first cell cycle so that the future ventral side is upward, two Nieuwkoop centers are formed, leading to two dorsal blastopore lips and two embryonic axes (see Figure 10.10). Therefore, the specification of the dorsal-ventral axis begins at the moment of sperm entry.
How does dorsal ventral pattern develop in Drosophila embryos?
The establishment of the dorsal-ventral pattern in Drosophila embryos depends on a signal transduction process: a putative extracellular ligand released into the perivitelline space surrounding the embryo binds to the Toll receptor.
What is the specification of the dorsal-ventral axis?
The specification of the dorsal-ventral axis takes place in several steps. The critical step is the translocation of the Dorsal protein from the cytoplasm into the nuclei of the ventral cells during the fourteenth division cycle.
What is the dorsal polarity of Drosophila?
Drosophila dorsal–ventral polarity from the oocyte to the first instar larva. The compass at the upper left indicates the direction of Anterior (A), Posterior (P), Dorsal (D), and Ventral (V) for each schematic drawing.
What is the Toll pathway in Drosophila embryogenesis?
During Drosophila embryogenesis, the Toll pathway establishes at least three different regions along the dorsoventral axis, resulting in the separation of the mesoderm and the neuroectoderm from the non-neurogenic (dorsal) ectoderm ( Figure 4) [ 15, 16 ].
