scholarly journals Spiny and soft-rayed fin domains in acanthomorph fish are established through a BMP-gremlin-shh signaling network

2021 ◽  
Vol 118 (29) ◽  
pp. e2101783118
Author(s):  
Rebekka Höch ◽  
Ralf F. Schneider ◽  
Alison Kickuth ◽  
Axel Meyer ◽  
Joost M. Woltering
Keyword(s):  
Transcription Factor ◽  
Convergent Evolution ◽  
Defense Mechanism ◽  
Cichlid Fish ◽  
Bmp Signaling ◽  
Developmental Program ◽  
Astatotilapia Burtoni ◽  
Evolutionary Success ◽  
Chemical Inhibition ◽  
Zone Of Polarizing Activity

With over 18,000 species, the Acanthomorpha, or spiny-rayed fishes, form the largest and arguably most diverse radiation of vertebrates. One of the key novelties that contributed to their evolutionary success are the spiny rays in their fins that serve as a defense mechanism. We investigated the patterning mechanisms underlying the differentiation of median fin Anlagen into discrete spiny and soft-rayed domains during the ontogeny of the direct-developing cichlid fish Astatotilapia burtoni. Distinct transcription factor signatures characterize these two fin domains, whereby mutually exclusive expression of hoxa13a/b with alx4a/b and tbx2b marks the spine to soft-ray boundary. The soft-ray domain is established by BMP inhibition via gremlin1b, which synergizes in the posterior fin with shh secreted from a zone of polarizing activity. Modulation of BMP signaling by chemical inhibition or gremlin1b CRISPR/Cas9 knockout induces homeotic transformations of spines into soft rays and vice versa. The expression of spine and soft-ray genes in nonacanthomorph fins indicates that a combination of exaptation and posterior expansion of an ancestral developmental program for the anterior fin margin allowed the evolution of robustly individuated spiny and soft-rayed domains. We propose that a repeated exaptation of such pattern might underly the convergent evolution of anterior spiny-fin elements across fishes.

scholarly journals The temporal transcription factor E93 controls dynamic enhancer activity and chromatin accessibility during development

2019 ◽  
Author(s):  
Spencer L. Nystrom ◽  
Matthew J. Niederhuber ◽  
Daniel J. McKay
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Developmental Time ◽  
Chromatin Accessibility ◽  
Wild Type ◽  
Spatial Cues ◽  
Enhancer Activity ◽  
Temporal Gene Expression ◽  
Developmental Program ◽  
Temporal Cues

ABSTRACTHow temporal cues combine with spatial inputs to control gene expression during development is poorly understood. Here, we test the hypothesis that the Drosophila transcription factor E93 controls temporal gene expression by regulating chromatin accessibility. Precocious expression of E93 early in wing development reveals that it can simultaneously activate and deactivate different target enhancers. Notably, the precocious patterns of enhancer activity resemble the wild-type patterns that occur later in development, suggesting that provision of E93 alters the competence of enhancers to respond to spatial cues. Genomic profiling reveals that precocious E93 expression is sufficient to regulate chromatin accessibility at a subset of its targets. These accessibility changes mimic those that normally occur later in development, indicating that precocious E93 accelerates the wild-type developmental program. Further, we find that target enhancers that do not respond to precocious E93 in early wings become responsive after a developmental transition, suggesting that parallel temporal pathways work alongside E93. These findings support a model wherein E93 expression functions as an instructive cue that defines a broad window of developmental time through control of chromatin accessibility.

scholarly journals The ETS-transcription factor Pointed is sufficient to regulate the posterior fate of the follicular epithelium

Development ◽  
2020 ◽  
Vol 147 (22) ◽  
pp. dev189787
Author(s):  
Cody A. Stevens ◽  
Nicole T. Revaitis ◽  
Rumkan Caur ◽  
Nir Yakoby
Keyword(s):  
Transcription Factor ◽  
Growth Factor Receptor ◽  
Bmp Signaling ◽  
Janus Kinase ◽  
Follicle Cells ◽  
Follicular Epithelium ◽  
T Box ◽  
Border Cell ◽  
Morphogenetic Protein ◽  
Ets Transcription Factor

ABSTRACTThe Janus-kinase/signal transducer and activator of transcription (JAK/STAT) pathway regulates the anterior posterior axis of the Drosophila follicle cells. In the anterior, it activates the bone morphogenetic protein (BMP) signaling pathway through expression of the BMP ligand decapentaplegic (dpp). In the posterior, JAK/STAT works with the epidermal growth factor receptor (EGFR) pathway to express the T-box transcription factor midline (mid). Although MID is necessary for establishing the posterior fate of the egg chamber, we show that it is not sufficient to determine a posterior fate. The ETS-transcription factor pointed (pnt) is expressed in an overlapping domain to mid in the follicle cells. This study shows that pnt is upstream of mid and that it is sufficient to induce a posterior fate in the anterior end, which is characterized by the induction of mid, the prevention of the stretched cells formation and the abrogation of border cell migration. We demonstrate that the anterior BMP signaling is abolished by PNT through dpp repression. However, ectopic DPP cannot rescue the anterior fate formation, suggesting additional targets of PNT participate in the posterior fate determination.

scholarly journals Heritability and adaptive significance of the number of egg-dummies in the cichlid fish Astatotilapia burtoni

2011 ◽  
Vol 278 (1716) ◽  
pp. 2318-2324 ◽  
Author(s):  
Topi K. Lehtonen ◽  
Axel Meyer
Keyword(s):  
Species Recognition ◽  
Cichlid Fish ◽  
Fertilization Success ◽  
Narrow Sense Heritability ◽  
Key Innovation ◽  
Bright Spots ◽  
Spot Number ◽  
Astatotilapia Burtoni ◽  
Important Trait ◽  
High Degree

Cichlid fishes are a textbook example of rapid speciation and exuberant diversity—this applies especially to haplochromines, a lineage with approximately 1800 species. Haplochromine males uniquely possess oval, bright spots on their anal fin, called ‘egg-spots’ or ‘egg-dummies’. These are presumed to be an evolutionary key innovation that contributed to the tribe's evolutionary success. Egg-spots have been proposed to mimic the ova of the mouthbrooding females of the corresponding species, contribute to fertilization success and even facilitate species recognition. Interestingly, egg-spot number varies extensively not only between species, but also within some populations. This high degree of intraspecific variation may appear to be counterintuitive since selection might be expected to act to stabilize traits that are correlated with fitness measures. We addressed this ‘paradox’ experimentally, and found that in the haplochromine cichlid Astatotilapia burtoni , the number of egg-spots was related to male age, body condition and dominance status. Intriguingly, the egg-spot number also had a high heritable component (narrow sense heritability of 0.5). These results suggest that the function of egg-spots might have less to do with fertilization success or species recognition, but rather relate to mate choice and/or male–male competition, helping to explain the high variability in this important trait.

Arginine vasotocin regulates social ascent in the African cichlid fish Astatotilapia burtoni

2015 ◽  
Vol 212 ◽  
pp. 106-113 ◽  
Author(s):  
Lin S. Huffman ◽  
Flora I. Hinz ◽  
Sophie Wojcik ◽  
Nadia Aubin-Horth ◽  
Hans A. Hofmann
Keyword(s):  
Cichlid Fish ◽  
Arginine Vasotocin ◽  
African Cichlid ◽  
Astatotilapia Burtoni

scholarly journals Androgen receptors in a cichlid fish,Astatotilapia burtoni: Structure, localization, and expression levels

2007 ◽  
Vol 504 (1) ◽  
pp. 57-73 ◽  
Author(s):  
Lene K. Harbott ◽  
Sabrina S. Burmeister ◽  
Richard B. White ◽  
Mike Vagell ◽  
Russell D. Fernald
Keyword(s):  
Androgen Receptors ◽  
Cichlid Fish ◽  
Expression Levels ◽  
Astatotilapia Burtoni
Sign in / Sign up

Export Citation Format

Share Document