Generation and early differentiation of glial cells in the first optic ganglion of Drosophila melanogaster

Development ◽  
1992 ◽  
Vol 115 (4) ◽  
pp. 903-911 ◽  
Author(s):  
M.L. Winberg ◽  
S.E. Perez ◽  
H. Steller
Keyword(s):  
Drosophila Melanogaster ◽  
Glial Cells ◽  
Enhancer Trap ◽  
P Element ◽  
Cell Divisions ◽  
Genetic Mosaic ◽  
First Optic Ganglion ◽  
Optic Ganglion ◽  
Glial Lineage ◽  
Enhancer Trap Lines

We have examined the generation and development of glial cells in the first optic ganglion, the lamina, of Drosophila melanogaster. Previous work has shown that the growth of retinal axons into the developing optic lobes induces the terminal cell divisions that generate the lamina monopolar neurons. We investigated whether photoreceptor ingrowth also influences the development of lamina glial cells, using P element enhancer trap lines, genetic mosaics and birthdating analysis. Enhancer trap lines that mark the differentiating lamina glial cells were found to require retinal innervation for expression. In mutants with only a few photoreceptors, only the few glial cells near ingrowing axons expressed the marker. Genetic mosaic analysis indicates that the lamina neurons and glial cells are readily separable, suggesting that these are derived from distinct lineages. Additionally, BrdU pulse-chase experiments showed that the cell divisions that produce lamina glia, unlike those producing lamina neurons, are not spatially or temporally correlated with the retinal axon ingrowth. Finally, in mutants lacking photoreceptors, cell divisions in the glial lineage appeared normal. We conclude that the lamina glial cells derive from a lineage that is distinct from that of the L-neurons, that glia are generated independently of photoreceptor input, and that completion of the terminal glial differentiation program depends, directly or indirectly, on an inductive signal from photoreceptor axons.

FGF3 and FGF8 mediate a rhombomere 4 signaling activity in the zebrafish hindbrain

Development ◽  
2002 ◽  
Vol 129 (16) ◽  
pp. 3825-3837 ◽  
Author(s):  
Lisa Maves ◽  
William Jackman ◽  
Charles B. Kimmel
Keyword(s):  
Neuronal Differentiation ◽  
Crucial Role ◽  
Time Lapse ◽  
Signaling Molecules ◽  
Neural Plate ◽  
Fgf Signaling ◽  
Genetic Mosaic ◽  
Signaling Center ◽  
Signaling Activity ◽  
Rhombomere 4

The segmentation of the vertebrate hindbrain into rhombomeres is highly conserved, but how early hindbrain patterning is established is not well understood. We show that rhombomere 4 (r4) functions as an early-differentiating signaling center in the zebrafish hindbrain. Time-lapse analyses of zebrafish hindbrain development show that r4 forms first and hindbrain neuronal differentiation occurs first in r4. Two signaling molecules, FGF3 and FGF8, which are both expressed early in r4, are together required for the development of rhombomeres adjacent to r4, particularly r5 and r6. Transplantation of r4 cells can induce expression of r5/r6 markers, as can misexpression of either FGF3 or FGF8. Genetic mosaic analyses also support a role for FGF signaling acting from r4. Taken together, our findings demonstrate a crucial role for FGF-mediated inter-rhombomere signaling in promoting early hindbrain patterning and underscore the significance of organizing centers in patterning the vertebrate neural plate.

Genetic Mosaic Labeling and Immunofluorescence Techniques in Zebrafish Brain

2015 ◽  
pp. 81-92
Author(s):  
Nobuhiko Miyasaka ◽  
Noriko Wakisaka ◽  
Yoshihiro Yoshihara
Keyword(s):  
Zebrafish Brain ◽  
Genetic Mosaic

scholarly journals A Genome-Wide Library of MADM Mice for Single-Cell Genetic Mosaic Analysis

2020 ◽  
Author(s):  
Ximena Contreras ◽  
Amarbayasgalan Davaatseren ◽  
Nicole Amberg ◽  
Andi H. Hansen ◽  
Johanna Sonntag ◽  
...  
Keyword(s):  
Single Cell ◽  
Genetic Mosaic ◽  
Genome Wide ◽  
A Genome ◽  
Mosaic Analysis

Eph signalling functions downstream of Val to regulate cell sorting and boundary formation in the caudal hindbrain

Development ◽  
2001 ◽  
Vol 128 (4) ◽  
pp. 571-580 ◽  
Author(s):  
J. Cooke ◽  
C. Moens ◽  
L. Roth ◽  
L. Durbin ◽  
K. Shiomi ◽  
...  
Keyword(s):  
Cell Sorting ◽  
Tyrosine Kinases ◽  
Bzip Transcription Factor ◽  
Boundary Formation ◽  
Spatial Regulation ◽  
Genetic Mosaic ◽  
Mosaic Approach ◽  
Mediate Cell ◽  
Neural Crest Migration ◽  
Mutant Cells

Rhombomeres are segmental units of the developing vertebrate hindbrain that underlie the reiterated organisation of cranial neural crest migration and neuronal differentiation. valentino (val), a zebrafish homologue of the mouse bzip transcription factor-encoding gene, kreisler, is required for segment boundary formation caudal to rhombomere 4 (r4). val is normally expressed in r5/6 and is required for cells to contribute to this region. In val(−) mutants, rX, a region one rhombomere in length and of mixed identity, lies between r4 and r7. While a number of genes involved in establishing rhombomeric identity are known, it is still largely unclear how segmental integrity is established and boundaries are formed. Members of the Eph family of receptor tyrosine kinases and their ligands, the ephrins, are candidates for functioning in rhombomere boundary formation. Indeed, expression of the receptor ephB4a coincides with val in r5/6, whilst ephrin-B2a, which encodes a ligand for EphB4a, is expressed in r4 and r7, complementary to the domain of val expression. Here we show that in val(−) embryos, ephB4a expression is downregulated and ephrin-B2a expression is upregulated between r4 and r7, indicating that Val is normally required to establish the mutually exclusive expression domains of these two genes. We show that juxtaposition of ephB4a-expressing cells and ephrin-B2a-expressing cells in the hindbrain leads to boundary formation. Loss of the normal spatial regulation of eph/ephrin expression in val mutants correlates not only with absence of boundaries but also with the inability of mutant cells to contribute to wild-type r5/6. Using a genetic mosaic approach, we show that spatially inappropriate Eph signalling underlies the repulsion of val(−) cells from r5/6. We propose that Val controls eph expression and that interactions between EphB4a and Ephrin-B2a mediate cell sorting and boundary formation in the segmenting caudal hindbrain.

Isolation and characterization of flightless mutants in Drosophila melanogaster

Development ◽  
1978 ◽  
Vol 45 (1) ◽  
pp. 123-143
Author(s):  
Takao Koana ◽  
Yoshiki Hotta
Keyword(s):  
Drosophila Melanogaster ◽  
Flight Muscle ◽  
Chromosomal Mapping ◽  
Indirect Flight Muscle ◽  
Mapping Technique ◽  
Isolation And Characterization ◽  
Genetic Mosaic ◽  
Column Type ◽  
Muscle Genes ◽  
Development And Differentiation

Since animal behaviour is executed through neuronal circuits including sensory receptors and muscle, genes vital for their development and differentiation must be found among mutants having behavioural anomaly. After mutagenesis with ethyl methanesulphonate (EMS), we screened for X-linked flightless mutants of Drosophila melanogaster by using a column-type flight tester. Approximately 104 individuals were screened and 21 mutant genes were isolated. Chromosomal mapping and complementation experiments revealed that they belong to 15 cistrons randomly located on X chromosome, three cistrons having more than two alleles. Two of the isolated mutants (AtO2 and AtH, which are recessive both behaviourally and morphologically) were analysed with the mosaic fate mapping technique, and both were found to have their primary foci in mesodermal region of blastoderm, suggesting that the genes exert their primary effect in indirect flight muscle. Electronmicroscopic studies on the muscles from four alleles of the AtO2 cistron revealed an abnormality in myofibrillar arrangement. A possible deficit within Z-band components is discussed in relation to wings-up B mutants. The indirect flight muscle of AltH was also examined, and it was found that sarcomere length and diameter of myofibrils were abnormal. It was postulated that a possible factor which controls size of myofibrils is defective in this mutant. These examples indicate the advantage of combining ultrastructural examination with genetic mosaic mapping technique.

Caenorhabditis elegans lin-25: cellular focus, protein expression and requirement for sur-2 during induction of vulval fates

Development ◽  
1998 ◽  
Vol 125 (23) ◽  
pp. 4809-4819 ◽  
Author(s):  
L. Nilsson ◽  
X. Li ◽  
T. Tiensuu ◽  
R. Auty ◽  
I. Greenwald ◽  
...  
Keyword(s):  
Protein Expression ◽  
Map Kinase ◽  
Signal Transduction Pathway ◽  
Precursor Cells ◽  
C Elegans ◽  
Novel Proteins ◽  
Genetic Mosaic ◽  
Mosaic Analysis ◽  
Map Kinase Pathway ◽  
Cell Fusions

Induction of vulval fates in the C. elegans hermaphrodite is mediated by a signal transduction pathway involving Ras and MAP kinase. Previous genetic analysis has suggested that two potential targets of this pathway in the vulva precursor cells are two novel proteins, LIN-25 and SUR-2. In this report, we describe further studies of lin-25. The results of a genetic mosaic analysis together with those of experiments in which lin-25 was expressed under the control of an heterologous promoter suggest that the major focus of lin-25 during vulva induction is the vulva precursor cells themselves. We have generated antisera to LIN-25 and used these to analyse the pattern of protein expression. LIN-25 is present in all six precursor cells prior to and during vulva induction but later becomes restricted to cells of the vulval lineages. Mutations in genes in the Ras/MAP kinase pathway do not affect the pattern of expression but the accumulation of LIN-25 is reduced in the absence of sur-2. Overexpression of LIN-25 does not rescue sur-2 mutant defects suggesting that LIN-25 and SUR-2 may function together. LIN-25 is also expressed in the lateral hypodermis. Overexpression of LIN-25 disrupts lateral hypodermal cell fusion, suggesting that lin-25 may play a role in regulating cell fusions in C. elegans.

A single frizzled protein has a dual function in tissue polarity

Development ◽  
1994 ◽  
Vol 120 (7) ◽  
pp. 1883-1893 ◽  
Author(s):  
R.E. Krasnow ◽  
P.N. Adler
Keyword(s):  
Dual Function ◽  
Protein Species ◽  
Hsp70 Promoter ◽  
Tissue Polarity ◽  
Genetic Mosaic ◽  
Single Protein ◽  
Genetic Epistasis ◽  
Pupal Wing ◽  
Separate Protein ◽  
Transgenic Flies

The Drosophila frizzled (fz) gene is required for the development of normal tissue polarity in the epidermis. Genetic epistasis experiments argue that fz is at the top of a regulatory hierarchy that controls the subcellular site for prehair initiation within the cells of the pupal wing (Wong and Adler, 1993; J. Cell Biol. 123, 209–221). Genetic mosaic experiments indicate that fz has both cell autonomous and cell non-autonomous functions that are separately mutable (Vinson and Adler, 1987; Nature 329, 549–551). Two species of fz mRNA have been identified, raising the question as to whether the two functions are provided by a single protein or by two separate protein species. We generated transgenic flies that express each of these mRNAs under the control of an hsp70 promoter. Only one of the transgenes (hsfzI) showed any fz activity. At 29 degrees C, the hsfzI transgene provided almost complete rescue of a null fz mutation, indicating that the protein encoded by this cDNA can fulfill both fz functions. Overexpression of the hsfzI transgene resulted in two distinct tissue polarity phenotypes depending on the time of heat shock.

scholarly journals The Dawn of the Age of Multi-Parent MAGIC Populations in Plant Breeding: Novel Powerful Next-Generation Resources for Genetic Analysis and Selection of Recombinant Elite Material

Biology ◽  
2020 ◽  
Vol 9 (8) ◽  
pp. 229 ◽  
Author(s):  
Andrea Arrones ◽  
Santiago Vilanova ◽  
Mariola Plazas ◽  
Giulio Mangino ◽  
Laura Pascual ◽  
...  
Keyword(s):  
Genetic Analysis ◽  
Plant Breeding ◽  
Complex Traits ◽  
Genetic Recombination ◽  
Phenotypic Diversity ◽  
Recombinant Inbred Lines ◽  
Plant Genetic Resources ◽  
Diallel Cross ◽  
Genetic Mosaic ◽  
Selection Of

The compelling need to increase global agricultural production requires new breeding approaches that facilitate exploiting the diversity available in the plant genetic resources. Multi-parent advanced generation inter-cross (MAGIC) populations are large sets of recombinant inbred lines (RILs) that are a genetic mosaic of multiple founder parents. MAGIC populations display emerging features over experimental bi-parental and germplasm populations in combining significant levels of genetic recombination, a lack of genetic structure, and high genetic and phenotypic diversity. The development of MAGIC populations can be performed using “funnel” or “diallel” cross-designs, which are of great relevance choosing appropriate parents and defining optimal population sizes. Significant advances in specific software development are facilitating the genetic analysis of the complex genetic constitutions of MAGIC populations. Despite the complexity and the resources required in their development, due to their potential and interest for breeding, the number of MAGIC populations available and under development is continuously growing, with 45 MAGIC populations in different crops being reported here. Though cereals are by far the crop group where more MAGIC populations have been developed, MAGIC populations have also started to become available in other crop groups. The results obtained so far demonstrate that MAGIC populations are a very powerful tool for the dissection of complex traits, as well as a resource for the selection of recombinant elite breeding material and cultivars. In addition, some new MAGIC approaches that can make significant contributions to breeding, such as the development of inter-specific MAGIC populations, the development of MAGIC-like populations in crops where pure lines are not available, and the establishment of strategies for the straightforward incorporation of MAGIC materials in breeding pipelines, have barely been explored. The evidence that is already available indicates that MAGIC populations will play a major role in the coming years in allowing for impressive gains in plant breeding for developing new generations of dramatically improved cultivars.

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