Interactions between the EGF receptor and DPP pathways establish distinct cell fates in the tracheal placodes

Development ◽  
1997 ◽  
Vol 124 (22) ◽  
pp. 4707-4716 ◽  
Author(s):  
P. Wappner ◽  
L. Gabay ◽  
B.Z. Shilo
Keyword(s):  
Egf Receptor ◽  
Cell Fates ◽  
Cell Divisions ◽  
Distinct Cell ◽  
Lateral Branches ◽  
Migration Of Cells ◽  
Antagonistic Interactions ◽  
Number Of Cells

The formation of the tracheal network in Drosophila is driven by stereotyped migration of cells from the tracheal pits. No cell divisions take place during tracheal migration and the number of cells in each branch is fixed. This work examines the basis for the determination of tracheal branch fates, prior to the onset of migration. We show that the EGF receptor pathway is activated by localized processing of the ligand SPITZ in the tracheal placodes and is responsible for the capacity to form the dorsal trunk and visceral branch. The DPP pathway, on the contrary, is induced in the tracheal pit by local presentation of DPP from the adjacent dorsal and ventral ectodermal cells. This pathway patterns the dorsal and lateral branches. Elimination of both pathways blocks migration of all tracheal branches. Antagonistic interactions between the two pathways are demonstrated. The opposing activities of two pathways may refine the final determination of tracheal branch fates.

EGF receptor signaling induces pointed P1 transcription and inactivates Yan protein in the Drosophila embryonic ventral ectoderm

Development ◽  
1996 ◽  
Vol 122 (11) ◽  
pp. 3355-3362 ◽  
Author(s):  
L. Gabay ◽  
H. Scholz ◽  
M. Golembo ◽  
A. Klaes ◽  
B.Z. Shilo ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Target Genes ◽  
Egf Receptor ◽  
Protein A ◽  
Drosophila Embryo ◽  
Cell Fates ◽  
Secondary Target ◽  
Graded Activity ◽  
Definition Of

The induction of different cell fates along the dorsoventral axis of the Drosophila embryo requires a graded activity of the EGF receptor tyrosine kinase (DER). Here we have identified primary and secondary target genes of DER, which mediate the determination of discrete ventral cell fates. High levels of DER activation in the ventralmost cells trigger expression of the transcription factors encoded by ventral nervous system defective (vnd) and pointed P1 (pntPl). Concomitant with the induction of pntP1, high levels of DER activity lead to inactivation of the Yan protein, a transcriptional repressor of Pointed-target genes. These two antagonizing transcription factors subsequently control the expression of secondary target genes such as otd, argos and tartan. The simultaneous effects of the DER pathway on pntP1 induction and Yan inactivation may contribute to the definition of the border of the ventralmost cell fates.

Sequential activation of the EGF receptor pathway during Drosophila oogenesis establishes the dorsoventral axis

Development ◽  
1998 ◽  
Vol 125 (2) ◽  
pp. 191-200 ◽  
Author(s):  
A. Sapir ◽  
R. Schweitzer ◽  
B.Z. Shilo
Keyword(s):  
Target Genes ◽  
Egf Receptor ◽  
Ectopic Expression ◽  
Follicle Cell ◽  
Follicle Cells ◽  
Cell Fates ◽  
Dorsoventral Axis ◽  
Spatial Coordinates ◽  
Sequential Activation

Previous work has demonstrated a role for the Drosophila EGF receptor (Torpedo/DER) and its ligand, Gurken, in the determination of anterioposterior and dorsoventral axes of the follicle cells and oocyte. The roles of DER in establishing the polarity of the follicle cells were examined further, by following the expression of DER-target genes. One class of genes (e.g. kekon) is induced by the DER pathway at all stages. Broad expression of kekon at the stage in which the follicle cells migrate posteriorly over the oocyte, demonstrates the capacity of the pathway to pattern all follicle cells except the ventral-most rows. This may provide the spatial coordinates for the ventral-most follicle cell fates. A second group of target genes (e.g. rhomboid (rho)) is induced only at later stages of oogenesis, and may require additional inputs by signals emanating from the anterior, stretch follicle cells. The function of Rho was analyzed by ectopic expression in the stretch follicle cells, and shown to induce a non-autonomous dorsalizing activity that is independent of Gurken. Rho thus appears to be involved in processing a DER ligand in the follicle cells, to pattern the egg chamber and allow persistent activation of the DER pathway during formation of the dorsal appendages.

The neurogenic locus brainiac cooperates with the Drosophila EGF receptor to establish the ovarian follicle and to determine its dorsal-ventral polarity

Development ◽  
1992 ◽  
Vol 116 (1) ◽  
pp. 177-192 ◽  
Author(s):  
S. Goode ◽  
D. Wright ◽  
A.P. Mahowald
Keyword(s):  
Nurse Cell ◽  
Egf Receptor ◽  
Ovarian Follicle ◽  
Follicle Cell ◽  
Cell Complex ◽  
Follicle Cells ◽  
Sensitive Period ◽  
Cell Fates ◽  
Genetic Mosaic

We have characterized the function of a new neurogenic locus, brainiac (brn), during oogenesis. Homozygous brn females lay eggs with fused dorsal appendages, a phenotype associated with torpedo (top) alleles of the Drosophila EGF receptor (DER) locus. By constructing double mutant females for both brn and top, we have found that brn is required for determining the dorsal-ventral polarity of the ovarian follicle. However, embryos from mature brn eggs develop a neurogenic phenotype which can be zygotically rescued if a wild-type sperm fertilizes the egg. This is the first instance of a Drosophila gene required for determination of dorsal-ventral follicle cell fates that is not required for determination of embryonic dorsal-ventral cell fates. The temperature-sensitive period for brn dorsal-ventral patterning begins at the inception of vitellogenesis. The interaction between brn and DER is also required for at least two earlier follicle cell activities which are necessary to establish the ovarian follicle. Prefollicular cells fail to migrate between each oocyte/nurse cell complex, resulting in follicles with multiple sets of oocytes and nurse cells. brn and DER function is also required for establishing and/or maintaining a continuous follicular epithelium around each oocyte/nurse cell complex. These brn functions as well as the brn requirement for determination of dorsal-ventral polarity appear to be genetically separable functions of the brn locus. Genetic mosaic experiments show that brn is required in the germline during these processes whereas the DER is required in the follicle cells. We propose that brn may be part of a germline signaling pathway differentially regulating successive DER-dependent follicle cell activities of migration, division and/or adhesion and determination during oogenesis. These experiments indicate that brn is required in both tyrosine kinase and neurogenic intercellular signaling pathways. Moreover, the functions of brn in oogenesis are distinct from those of Notch and Delta, two other neurogenic loci that are known to be required for follicular development.

EGF receptor attenuates Dpp signaling and helps to distinguish the wing and leg cell fates in Drosophila

Development ◽  
2000 ◽  
Vol 127 (17) ◽  
pp. 3769-3776 ◽  
Author(s):  
K. Kubota ◽  
S. Goto ◽  
K. Eto ◽  
S. Hayashi
Keyword(s):  
Spatial Distribution ◽  
Cell Fate ◽  
Receptor Tyrosine Kinase ◽  
Egf Receptor ◽  
Homeobox Gene ◽  
Cell Fate Decision ◽  
Cell Fates ◽  
Dorsoventral Axis ◽  
Fate Decision ◽  
Number Of Cells

Wing and leg precursors of Drosophila are recruited from a common pool of ectodermal cells expressing the homeobox gene Dll. Induction by Dpp promotes this cell fate decision toward the wing and proximal leg. We report here that the receptor tyrosine kinase EGFR antagonizes the wing-promoting function of Dpp and allows recruitment of leg precursor cells from uncommitted ectodermal cells. By monitoring the spatial distribution of cells responding to Dpp and EGFR, we show that nuclear transduction of the two signals peaks at different position along the dorsoventral axis when the fates of wing and leg discs are specified and that the balance of the two signals assessed within the nucleus determines the number of cells recruited to the wing. Differential activation of the two signals and the cross talk between them critically affect this cell fate choice.

scholarly journals On the edge: Evolution of polarity protein BASL and the capacity for stomatal lineage asymmetric divisions

2021 ◽  
Author(s):  
Ido Nir ◽  
Gabriel O Amador ◽  
Yan Gong ◽  
Nicole K Smoot ◽  
Le Cai ◽  
...  
Keyword(s):  
Cell Fate ◽  
Cell Types ◽  
Cell Fates ◽  
Division Plane ◽  
Asymmetric Cell Divisions ◽  
Cell Divisions ◽  
Distinct Cell ◽  
Asymmetric Divisions ◽  
Stem Cell Divisions ◽  
Stomatal Lineage

Asymmetric and oriented stem cell divisions enable the continued production of patterned tissues. The molecules that guide these divisions include several polarity proteins that are localized to discrete plasma membrane domains, are differentially inherited during asymmetric divisions, and whose scaffolding activities can guide division plane orientation and subsequent cell fates. In the stomatal lineages on the surfaces of plant leaves, asymmetric and oriented divisions create distinct cell types in physiologically optimized patterns. The polarity protein BASL is a major regulator of stomatal lineage division and cell fate asymmetries in Arabidopsis, but its role in the stomatal lineages of other plants was unclear. Here, using phylogenetic and functional assays, we demonstrate that BASL is a dicot specific polarity protein. Among dicots, divergence in BASLs roles may reflect some intrinsic protein differences, but more likely reflects previously unappreciated differences in how asymmetric cell divisions are employed for pattern formation in different species. This multi-species analysis therefore provides insight into the evolution of a unique polarity regulator and into the developmental choices available to cells as they build and pattern tissues.

scholarly journals spalt-dependent switching between two cell fates that are induced by the Drosophila EGF receptor

Development ◽  
2001 ◽  
Vol 128 (5) ◽  
pp. 723-732 ◽  
Author(s):  
P.R. Elstob ◽  
V. Brodu ◽  
A.P. Gould
Keyword(s):  
Cell Fate ◽  
Animal Species ◽  
Egf Receptor ◽  
Zinc Finger Protein ◽  
Cell Types ◽  
Chordotonal Organ ◽  
Egfr Signaling ◽  
Cell Fates ◽  
Finger Protein ◽  
Distinct Cell

Signaling from the EGF receptor (EGFR) can trigger the differentiation of a wide variety of cell types in many animal species. We have explored the mechanisms that generate this diversity using the Drosophila peripheral nervous system. In this context, Spitz (SPI) ligand can induce two alternative cell fates from the dorsolateral ectoderm: chordotonal sensory organs and non-neural oenocytes. We show that the overall number of both cell types that are induced is controlled by the degree of EGFR signaling. In addition, the spalt (sal) gene is identified as a critical component of the oenocyte/chordotonal fate switch. Genetic and expression analyses indicate that the SAL zinc-finger protein promotes oenocyte formation and supresses chordotonal organ induction by acting both downstream and in parallel to the EGFR. To explain these findings, we propose a prime-and-respond model. Here, sal functions prior to signaling as a necessary but not sufficient component of the oenocyte prepattern that also serves to raise the apparent threshold for induction by SPI. Subsequently, sal-dependent SAL upregulation is triggered as part of the oenocyte-specific EGFR response. Thus, a combination of SAL in the responding nucleus and increased SPI ligand production sets the binary cell-fate switch in favour of oenocytes. Together, these studies help to explain how one generic signaling pathway can trigger the differentiation of two distinct cell types.

PENENTUAN KRITERIA PENILAIAN KESAN JUMLAH LEUKOSIT PADA PEMERIKSAAN APUSAN DARAH TEPI

2018 ◽  
Vol 3 (2) ◽  
pp. 52-61
Author(s):  
Dzikra Arwie ◽  
Islawati
Keyword(s):  
Data Analysis ◽  
Statistical Analysis ◽  
Blood Cells ◽  
Blood Smear ◽  
White Blood Cells ◽  
Peripheral Blood Smear ◽  
Field Of View ◽  
Laboratory Observation ◽  
Number Of Cells

Leukocytes or white blood cells have a characteristic characteristic of different cells. Determination of the impression of the number of leukocytes is determined in the number of cells in the field of view. While the number of viewable field cells expressed is still quite varied. The purpose of this study was to determine the number of leukocytes in the field of view and expressed the impression of a sufficient amount. This research was conducted at the Laboratory of Health Analyst Department Panrita Husada Bulukumba on 9 April 2017 to 14 July 2017. This type of research is a laboratory observation that aims to determine the criteria for assessing the impression of the number of leukocytes on a peripheral blood smear. Data analysis using statistical analysis is the average and standard deviations to determine the impression of the number of leukocytes and use 3 inspection zones. The results of this study obtained results in zone IV the number of leukocyte impressions said to be sufficient was 7-10, in zone V the number of leukocyte impressions said to be sufficient was 4-9, and in zone VI the number of leukocyte impressions said to be sufficient was 3-8.  

scholarly journals Quantitation of mast cell heparin by flow cytofluorometry.

1976 ◽  
Vol 24 (12) ◽  
pp. 1231-1238 ◽  
Author(s):  
L Enerbäck ◽  
G Berlin ◽  
I Svensson ◽  
I Rundquist
Keyword(s):  
Mast Cell ◽  
Mast Cells ◽  
Mixed Cell ◽  
Flow Cytofluorometry ◽  
Frequency Distributions ◽  
Cell Counts ◽  
Mixed Cell Population ◽  
Number Of Cells ◽  
Excellent Reproducibility

Mast cells can be automatically identified in a mixed cell population by flow cytofluorometry after Berberine sulphate staining. Volume specific counts of the total number of cells and number of mast cells, as well as frequency distributions of fluorescence intensities of mast cells, based on a large number of cells, can be rapidly obtained. Results obtained by microscope fluorometry of cells identified by phase contrast microscopy showviously published results it may be inferred that the fluorescence intensity of individual mast cells is proportional to mast cell heparin content. The automated cell counts correlated very well with manual hemocytometer counts. Both cell counts and the determination of mean mast cell fluorescence showed excellent reproducibility.

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