The smad5 mutation somitabun blocks Bmp2b signaling during early dorsoventral patterning of the zebrafish embryo

Development ◽  
1999 ◽  
Vol 126 (10) ◽  
pp. 2149-2159 ◽  
Author(s):  
M. Hild ◽  
A. Dick ◽  
G.J. Rauch ◽  
A. Meier ◽  
T. Bouwmeester ◽  
...  
Keyword(s):  
Zebrafish Embryo ◽  
Expression Patterns ◽  
Marker Gene ◽  
Single Amino Acid ◽  
Dorsoventral Patterning ◽  
Wild Type ◽  
Cell Fates ◽  
Marker Gene Expression ◽  
Smad Proteins ◽  
Set Up

Signaling by members of the TGFbeta superfamily is thought to be transduced by Smad proteins. Here, we describe a zebrafish mutant in smad5, designated somitabun (sbn). The dominant maternal and zygotic effect of the sbntc24 mutation is caused by a change in a single amino acid in the L3 loop of Smad5 protein which transforms Smad5 into an antimorphic version, inhibiting wild-type Smad5 and related Smad proteins. sbn mutant embryos are strongly dorsalized, similarly to mutants in Bmp2b, its putative upstream signal. Double mutant analyses and RNA injection experiments show that sbn and bmp2b interact and that sbn acts downstream of Bmp2b signaling to mediate Bmp2b autoregulation during early dorsoventral (D-V) pattern formation. Comparison of early marker gene expression patterns, chimera analyses and rescue experiments involving temporally controlled misexpression of bmp or smad in mutant embryos reveal three phases of D-V patterning: an early sbn- and bmp2b-independent phase when a coarse initial D-V pattern is set up, an intermediate sbn- and bmp2b-dependent phase during which the putative morphogenetic Bmp2/4 gradient is established, and a later sbn-independent phase during gastrulation when the Bmp2/4 gradient is interpreted and cell fates are specified.

Patterning of angiogenesis in the zebrafish embryo

Development ◽  
2002 ◽  
Vol 129 (4) ◽  
pp. 973-982 ◽  
Author(s):  
Sarah Childs ◽  
Jau-Nian Chen ◽  
Deborah M. Garrity ◽  
Mark C. Fishman
Keyword(s):  
Zebrafish Embryo ◽  
Regular Pattern ◽  
Wild Type ◽  
Cell Fates ◽  
Mutagenesis Screen ◽  
The Third ◽  
Shaped Cell ◽  
Vessel Growth ◽  
Lateral Posterior ◽  
Lineage Analysis

Little is known about how vascular patterns are generated in the embryo. The vasculature of the zebrafish trunk has an extremely regular pattern. One intersegmental vessel (ISV) sprouts from the aorta, runs between each pair of somites, and connects to the dorsal longitudinal anastomotic vessel (DLAV). We now define the cellular origins, migratory paths and cell fates that generate these metameric vessels of the trunk. Additionally, by a genetic screen we define one gene, out of bounds (obd), that constrains this angiogenic growth to a specific path. We have performed lineage analysis, using laser activation of a caged dye and mosaic construction to determine the origin of cells that constitute the ISV. Individual angioblasts destined for the ISVs arise from the lateral posterior mesoderm (LPM), and migrate to the dorsal aorta, from where they migrate between somites to their final position in the ISVs and dorsal longitudinal anastomotic vessel (DLAV). Cells of each ISV leave the aorta only between the ventral regions of two adjacent somites, and migrate dorsally to assume one of three ISV cell fates. Most dorsal is a T-shaped cell, based in the DLAV and branching ventrally; the second constitutes a connecting cell; and the third an inverted T-shaped cell, based in the aorta and branching dorsally. The ISV remains between somites during its ventral course, but changes to run mid-somite dorsally. This suggests that the pattern of ISV growth ventrally and dorsally is guided by different cues. We have also performed an ENU mutagenesis screen of 750 mutagenized genomes and identified one mutation, obd that disrupts this pattern. In obd mutant embryos, ISVs sprout precociously at abnormal sites and migrate anomalously in the vicinity of ventral somite. The dorsal extent of the ISV is less perturbed. Precocious sprouting can be inhibited in a VEGF morphant, but the anomalous site of origin of obd ISVs remains. In mosaic embryos, obd somite causes adjacent wild-type endothelial cells to assume the anomalous ISV pattern of obd embryos. Thus, the launching position of the new sprout and its initial trajectory are directed by inhibitory signals from ventral somites. Zebrafish ISVs are a tractable system for defining the origins and fates of vessels, and for dissecting elements that govern patterns of vessel growth.

Essential role of Bmp7 (snailhouse) and its prodomain in dorsoventral patterning of the zebrafish embryo

Development ◽  
2000 ◽  
Vol 127 (2) ◽  
pp. 343-354 ◽  
Author(s):  
A. Dick ◽  
M. Hild ◽  
H. Bauer ◽  
Y. Imai ◽  
H. Maifeld ◽  
...  
Keyword(s):  
Bone Morphogenetic Proteins ◽  
Double Mutant ◽  
Essential Role ◽  
Zebrafish Embryo ◽  
Temperature Sensitive ◽  
Dorsoventral Patterning ◽  
Cell Fates ◽  
Higher Temperature ◽  
Reduced Activity

Bone morphogenetic proteins (Bmps) are signaling molecules that have been implicated in a variety of inductive processes. We report here that zebrafish Bmp7 is disrupted in snailhouse (snh) mutants. The allele snh(st1) is a translocation deleting the bmp7 gene, while snh(ty68) displays a Val->Gly exhange in a conserved motif of the Bmp7 prodomain. The snh(ty68) mutation is temperature-sensitive, leading to severalfold reduced activity of mutant Bmp7 at 28 degrees C and non-detectable activity at 33 degrees C. This prodomain lesion affects secretion and/or stability of secreted mature Bmp7 after processing has occurred. Both snh(st1) and snh(ty68) mutant zebrafish embryos are strongly dorsalized, indicating that bmp7 is required for the specification of ventral cell fates during early dorsoventral patterning. At higher temperature, the phenotype of snh(ty68) mutant embryos is identical to that caused by the amorphic bmp2b mutation swirl swr(ta72) and similar to that caused by the smad5 mutation somitabun sbn(dtc24). mRNA injection studies and double mutant analyses indicate that Bmp2b and Bmp7 closely cooperate and that Bmp2b/Bmp7 signaling is transduced by Smad5 and antagonized by Chordino.

scholarly journals Characterization of a Novel Rice Dynamic Narrow-Rolled Leaf Mutant with Deficiencies in Aromatic Amino Acids

2020 ◽  
Vol 21 (4) ◽  
pp. 1521
Author(s):  
Huimei Wang ◽  
Yongfeng Shi ◽  
Xiaobo Zhang ◽  
Xia Xu ◽  
Jian-Li Wu
Keyword(s):  
Amino Acids ◽  
Expression Patterns ◽  
Critical Role ◽  
Aromatic Amino Acids ◽  
Single Amino Acid ◽  
Wild Type ◽  
Leaf Morphogenesis ◽  
Leaf Phenotype ◽  
Single Amino Acid Change ◽  
Rolled Leaf

The leaf blade is the main photosynthetic organ and its morphology is related to light energy capture and conversion efficiency. We isolated a novel rice Dynamic Narrow-Rolled Leaf 1 (dnrl1) mutant showing reduced width of leaf blades, rolled leaves and lower chlorophyll content. The narrow-rolled leaf phenotype resulted from the reduced number of small longitudinal veins per leaf, smaller size and irregular arrangement of bulliform cells compared with the wild-type. DNRL1 was mapped to chromosome 7 and encoded a putative 3-deoxy-7-phosphoheptulonate synthase (DAHPS) which catalyzes the conversion of phosphoenolpyruvate and D-erythrose 4-phosphate to DAHP and phosphate. Sequence analysis revealed that a single base substitution (T–A) was detected in dnrl1, leading to a single amino acid change (L376H) in the coding protein. The mutation led to a lower expression level of DNRL1 as well as the lower activity of DAHPS in the mutant compared with the wild type. Genetic complementation and over-expression of DNRL1 could rescue the narrow-rolled phenotype. DNRL1 was constitutively expressed in all tested organs and exhibited different expression patterns from other narrow-rolled leaf genes. DNRL1-GFP located to chloroplasts. The lower level of chlorophyll in dnrl1 was associated with the downregulation of the genes responsible for chlorophyll biosynthesis and photosynthesis. Furthermore, dnrl1 showed significantly reduced levels of aromatic amino acids including Trp, Phe and Tyr. We conclude that OsDAHPS, encoded by DNRL1, plays a critical role in leaf morphogenesis by mediating the biosynthesis of amino acids in rice.

scholarly journals EARLY FLOWERING 3 and Photoperiod Sensing in Brachypodium distachyon

2022 ◽  
Vol 12 ◽  
Author(s):  
Frédéric Bouché ◽  
Daniel P. Woods ◽  
Julie Linden ◽  
Weiya Li ◽  
Kevin S. Mayer ◽  
...  
Keyword(s):  
Clock Genes ◽  
Brachypodium Distachyon ◽  
Expression Patterns ◽  
Marker Gene ◽  
Red Light ◽  
Early Flowering ◽  
Day Length ◽  
Wild Type ◽  
Complex Protein ◽  
Short Days

The proper timing of flowering, which is key to maximize reproductive success and yield, relies in many plant species on the coordination between environmental cues and endogenous developmental programs. The perception of changes in day length is one of the most reliable cues of seasonal change, and this involves the interplay between the sensing of light signals and the circadian clock. Here, we describe a Brachypodium distachyon mutant allele of the evening complex protein EARLY FLOWERING 3 (ELF3). We show that the elf3 mutant flowers more rapidly than wild type plants in short days as well as under longer photoperiods but, in very long (20 h) days, flowering is equally rapid in elf3 and wild type. Furthermore, flowering in the elf3 mutant is still sensitive to vernalization, but not to ambient temperature changes. Molecular analyses revealed that the expression of a short-day marker gene is suppressed in elf3 grown in short days, and the expression patterns of clock genes and flowering time regulators are altered. We also explored the mechanisms of photoperiodic perception in temperate grasses by exposing B. distachyon plants grown under a 12 h photoperiod to a daily night break consisting of a mixture of red and far-red light. We showed that 2 h breaks are sufficient to accelerate flowering in B. distachyon under non-inductive photoperiods and that this acceleration of flowering is mediated by red light. Finally, we discuss advances and perspectives for research on the perception of photoperiod in temperate grasses.

scholarly journals Atlas of Prenatal Hair Follicle Morphogenesis Using the Pig as a Model System

2021 ◽  
Vol 9 ◽  
Author(s):  
Yao Jiang ◽  
Quan Zou ◽  
Bo Liu ◽  
Shujuan Li ◽  
Yi Wang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Hair Follicle ◽  
Human Hair ◽  
Scalp Hair ◽  
Expression Patterns ◽  
Marker Gene ◽  
Morphological Observation ◽  
Suitable Model ◽  
Type I ◽  
Marker Gene Expression

The pig is an increasingly popular biomedical model, but only a few in depth data exist on its studies in hair follicle (HF) morphogenesis and development. Hence, the objective of this study was to identify the suitability of the pig as an animal model for human hair research. We performed a classification of pig HF morphogenesis stages and hair types. All four different hair types sampled from 17 different body parts in pig were similar to those of human. The Guard_2 sub-type was more similar to type II human scalp hair while Guard_1, Awl, Auchene, and Zigzag were similar to type I scalp hair. Based on morphological observation and marker gene expression of HF at 11 different embryonic days and six postnatal days, we classified pig HF morphogenesis development from E41 to P45 into three main periods – induction (E37–E41), organogenesis (E41–E85), and cytodifferentiation (>E85). Furthermore, we demonstrated that human and pig share high similarities in HF morphogenesis occurrence time (early/mid gestational) and marker gene expression patterns. Our findings will facilitate the study of human follicle morphogenesis and research on complex hair diseases and offer researchers a suitable model for human hair research.

Dorsoventral axis formation in Drosophila depends on the correct dosage of the gene gurken

Development ◽  
1994 ◽  
Vol 120 (9) ◽  
pp. 2457-2463 ◽  
Author(s):  
F.S. Neuman-Silberberg ◽  
T. Schupbach
Keyword(s):  
Germ Line ◽  
Follicle Cell ◽  
Follicle Cells ◽  
Limiting Factor ◽  
Axis Formation ◽  
Dorsoventral Patterning ◽  
Wild Type ◽  
Cell Fates ◽  
Dorsoventral Axis ◽  
Signaling Process

The Drosophila gene gurken participates in a signaling process that occurs between the germ line and the somatic cells (follicle cells) of the ovary. This process is required for correct patterning of the dorsoventral axis of both the egg and the embryo. gurken produces a spatially localized transcript which encodes a TGF-alpha-like molecule (Neuman-Silberberg and Schupbach, Cell 75, 165–174, 1993). Mutations in gurken cause a ventralized phenotype in egg and embryo. To determine whether the gurken gene product plays an instructive role in dorsoventral patterning, we constructed females containing extra copies of a gurken transgene. Such females produce dorsalized eggs and embryos, which is expected if gurken acts as a limiting factor in the dorsoventral patterning process. In addition, the expression pattern of the gene rhomboid in the follicle cells is altered in ovaries of females containing extra copies of gurken. Our results indicate that changing gurken dosage in otherwise wild-type ovaries is sufficient to alter the number of somatic follicle cells directed to the dorsal fate. Therefore the gurken-torpedo signaling process plays an instructive role in oogenesis. It induces dorsal cell fates in the follicle cell epithelium and it controls the production of maternal components that will direct the embryonic dorsoventral pattern after fertilization.

The molecular nature of zebrafish swirl: BMP2 function is essential during early dorsoventral patterning

Development ◽  
1997 ◽  
Vol 124 (22) ◽  
pp. 4457-4466 ◽  
Author(s):  
Y. Kishimoto ◽  
K.H. Lee ◽  
L. Zon ◽  
M. Hammerschmidt ◽  
S. Schulte-Merker
Keyword(s):  
Pattern Formation ◽  
Bone Morphogenetic Proteins ◽  
Zebrafish Embryo ◽  
Mutant Phenotype ◽  
Mesoderm Induction ◽  
Dorsoventral Patterning ◽  
Wild Type ◽  
Maternal Role ◽  
Vertebrate Embryos ◽  
Molecular Nature

Early dorsoventral pattern formation in vertebrate embryos is regulated by opposing activities of ventralizing bone morphogenetic proteins (BMPs) and dorsal-specific BMP antagonists such as Chordin, Noggin and Follistatin. Specific defects in early dorsoventral patterning have been recently found in a number of zebrafish mutants, which exhibit either a ventralized or dorsalized phenotype. One of these, the ventralized mutant chordino (originally called dino) is caused by a mutation in the zebrafish chordin homologue and interacts genetically with the dorsalized mutant swirl. In swirl mutant embryos, dorsal structures such as notochord and somites are expanded while ventral structures such as blood and nephros are missing. Here we demonstrate that the swirl phenotype is caused by mutations in the zebrafish bmp2 gene (zbmp2). While injection of mRNAs encoded by the mutant alleles has no ventralizing effect, injection of wild-type zbmp2 mRNA leads to a complete rescue of the swirl mutant phenotype. Fertile adult mutant fish were obtained, showing that development after gastrulation is not dependent on zbmp2 function. In addition zBMP2 has no maternal role in mesoderm induction. Our analysis shows that swirl/BMP2, unlike mouse BMP2 but like mouse BMP4, is required for early dorsoventral patterning of the zebrafish embryo.

scholarly journals A gene expression atlas of abicoid-depleted Drosophila embryo reveals early canalization of cell fate

2014 ◽  
Author(s):  
Max V Staller ◽  
Charless C Fowlkes ◽  
Meghan D.J. Bragdon ◽  
Zeba B. Wunderlich ◽  
Angela DePace
Keyword(s):  
Gene Expression ◽  
Cell Fate ◽  
Early Stage ◽  
Expression Patterns ◽  
Drosophila Embryo ◽  
Wild Type ◽  
Cell Fates ◽  
Gene Expression Atlas ◽  
Expression Atlas ◽  
Gene Regulatory

In developing embryos, gene regulatory networks canalize cells towards discrete terminal fates. We studied the behavior of the anterior-posterior segmentation network in Drosophila melanogaster embryos depleted of a key maternal input, bicoid (bcd), by building a cellular- resolution gene expression atlas containing measurements of 12 core patterning genes over 6 time points in early development. With this atlas, we determine the precise perturbation each cell experiences, relative to wild type, and observe how these cells assume cell fates in the perturbed embryo. The first zygotic layer of the network, consisting of the gap and terminal genes, is highly robust to perturbation: all combinations of transcription factor expression found in bcd depleted embryos were also found in wild type embryos, suggesting that no new cell fates were created even at this very early stage. All of the gap gene expression patterns in the trunk expand by different amounts, a feature that we were unable to explain using two simple models of the effect of bcd depletion. In the second layer of the network, depletion of bcd led to an excess of cells expressing both even skipped and fushi tarazu early in the blastoderm stage, but by gastrulation this overlap resolved into mutually exclusive stripes. Thus, following depletion of bcd, individual cells rapidly canalize towards normal cell fates in both layers of this gene regulatory network. Our gene expression atlas provides a high resolution picture of a classic perturbation and will enable further modeling of canalization in this transcriptional network.

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