Sally A Moody

George Washington University | GW · Department of Anatomy and Regenerative Biology

Normal tables of development are essential for studies of embryogenesis, serving as an important resource for model organisms, including the frog Xenopus laevis. Xenopus has long been used to study developmental and cell biology, and is an increasingly important model for human birth defects and disease, genomics, proteomics and toxicology. Scienti...

Each year approximately 35% of babies are born with craniofacial abnormalities of the skull, jaws, ears, and/or teeth, which in turn can lead to problems in feeding, hearing, and sight [...]

Mcrs1 is a multifunctional protein that is critical for many cellular processes in a wide range of cell types. Previously, we showed that Mcrs1 binds to the Six1 transcription factor and reduces the ability of the Six1-Eya1 complex to upregulate transcription, and that Mcrs1 loss-of-function leads to the expansion of several neural plate genes, red...

Branchio-oto-renal syndrome (BOR) is a condition that presents with variable craniofacial, otic, and/or renal malformations. Half of the BOR patients have a mutation in SIX1or its co-factor EYA1. As the other 50% of cases are of unknown cause, it is important to identify other putative co-factors of SIX1 that may contribute to BOR. A screen of the...

Retinoic acid (RA) is a central regulatory signal that controls numerous developmental processes in vertebrate embryos. Although activation of Hox expression is considered one of the earliest functions of RA signaling in the embryo, there is evidence that embryos are poised to initiate RA signaling just before gastrulation begins, and manipulations...

The embryonic ectoderm is composed of four domains: neural plate, neural crest, pre-placodal region (PPR) and epidermis. Their formation is initiated during early gastrulation by dorsal-ventral and anterior-posterior gradients of signaling factors that first divide the embryonic ectoderm into neural and non-neural domains. Next, the neural crest an...

The vertebrate Six (Sine oculis homeobox) family of homeodomain transcription factors plays critical roles in the development of several organs. Six1 plays a central role in cranial placode development, including the precursor tissues of the inner ear, as well as other cranial sensory organs and the kidney. In humans, mutations in SIX1 underlie som...

Branchio-oto-renal syndrome (BOR) is a disorder characterized by hearing loss, craniofacial and/or renal defects. Variants in the transcription factor Six1 and its cofactor Eya1, both required for otic development, are linked to BOR. We previously identified Sobp as a potential Six1 cofactor and SOBP variants in mouse and humans cause otic phenotyp...

The vertebrate Six (Sine oculis homeobox) family of homeodomain transcription factors play critical roles in the development of several organs. Six1 plays a central role in cranial placode development, including the precursor tissues of the inner ear, as well as other cranial sensory organs and the kidney. In humans, mutations in SIX1 underlie some...

Several single-nucleotide mutations in SIX1 underlie branchio-otic/branchio-oto-renal (BOR) syndrome, but the clinical literature has not been able to correlate different variants with specific phenotypes. We previously assessed whether variants in either the cofactor binding domain (V17E, R110W) or the DNA binding domain (W122R, Y129C) might diffe...

Single nucleotide mutations in SIX1 are causative in some individuals diagnosed with branchiootic/branchio-oto-renal (BOR) syndrome. To test whether these mutations have differential effects on otic gene expression, we engineered four BOR mutations in Xenopus six1 and targeted mutant protein expression to the neural crest and cranial placode precur...

The left–right (L–R) axis of most bilateral animals is established during gastrulation when a transient ciliated structure creates a directional flow of signaling molecules that establish asymmetric gene expression in the lateral plate mesoderm. However, in some animals, an earlier differential distribution of molecules and cell division patterns i...

Branchio-oto-renal syndrome (BOR) is a disorder characterized by hearing loss, craniofacial and/or renal defects. Mutations in the transcription factor Six1 and its cofactor Eya1, both required for otic development, are linked to BOR. We previously identified Sobp as a potential Six1 cofactor and SOBP mutations in mouse and humans cause otic phenot...

22q11.2 Deletion Syndrome (22q11DS) is a neurodevelopmental disorder associated with cranial nerve anomalies and disordered oropharyngeal function including pediatric dysphagia. Using the LgDel 22q11DS mouse model, we asked whether sensory neuron differentiation in the trigeminal ganglion (CNgV) , which is essential for normal orofacial function, i...

The Society for Craniofacial Genetics and Developmental Biology (SCGDB) held its 43rd annual meeting in a virtual format on October 19–20, 2020. The SCGDB meeting included the presentation of the SCGDB Distinguished Scientists in Craniofacial Research Awards to Marilyn Jones and Kerstin Ludwig and four scientific sessions on the molecular regulatio...

We identified divergent modes of initial axon growth that prefigure disrupted differentiation of the trigeminal nerve (CN V), a cranial nerve essential for suckling, feeding and swallowing (S/F/S), a key innate behavior compromised in multiple genetic developmental disorders including DiGeorge/22q11.2 Deletion Syndrome (22q11.2 DS). We combined rap...

The Six1 transcription factor plays a major role in craniofacial development. Mutations in SIX1 and its co-factor, EYA1, are causative for about 50% of Branchio-otic/Branchio-oto-renal syndrome (BOR) patients, who are characterized by variable craniofacial, otic and renal malformations. We previously screened for other proteins that might interact...

All mammals must suckle and swallow at birth, and subsequently chew and swallow solid foods, for optimal growth and health. These initially innate behaviors depend critically upon coordinated development of the mouth, tongue, pharynx, and larynx as well as the cranial nerves that control these structures. Disrupted suckling, feeding, and swallowing...

LgDel mice, which model the heterozygous deletion of genes at human chromosome 22q11.2 associated with DiGeorge/22q11.2 deletion syndrome (22q11DS), have cranial nerve and craniofacial dysfunction as well as disrupted suckling, feeding and swallowing, similar to key 22q11DS phenotypes. Divergent trigeminal nerve (CN V) differentiation and altered t...

Xenopus laevis frogs from laboratory stocks normally lay eggs with extensive size variability. We find that these initial size differences subsequently affect the size of the embryos prior to the onset of growth, and the size of tadpoles during the growth period. Even though these tadpoles differ in size, their tissues, organs, and structures alway...

The Society for Craniofacial Genetics and Developmental Biology (SCGDB) 42nd Annual Meeting was held at the MD Anderson Cancer Center in Houston, Texas from October 14–15, 2019. The SCGDB meeting included scientific sessions on the molecular regulation of craniofacial development, cell biology of craniofacial development, signaling during craniofac...

LgDel mice, which model the heterozygous deletion of genes at human chromosome 22q11.2 associated with DiGeorge/22q11.2 Deletion Syndrome (22q11DS), have cranial nerve and craniofacial dysfunction as well as disrupted suckling, feeding, and swallowing, similar to key 22q11DS phenotypes. Divergent trigeminal nerve (CN V) differentiation and altered...

Single nucleotide mutations in human SIX1 result in amino acid substitutions in either the protein-protein interaction domain or the homeodomain and cause about 4% of branchio-otic (BOS) and branchio-oto-renal (BOR) patients. The phenotypic variation between patients with the same mutation, even within affected members of the same family, make it d...

Label-free single-cell proteomics by mass spectrometry (MS) is currently incompatible with complex tissues without requiring cell culturing, single-cell dissection, or tissue dissociation. We here report the first example of label-free single-cell MS-based proteomics directly in single cells in live vertebrate embryos. Our approach integrates optic...

The specialized sensory organs of the vertebrate head are derived from thickened patches of cells in the ectoderm called cranial sensory placodes. The developmental program that generates these placodes and the genes that are expressed during the process have been studied extensively in a number of animals, yet very little is known about how these...

The molecular program by which embryonic ectoderm is induced to form neural tissue is essential to understanding normal and impaired development of the central nervous system. Xenopus has been a powerful vertebrate model in which to elucidate this process. However, abundant vitellogenin (yolk) proteins in cells of the early Xenopus embryo interfere...

The quantification of small molecules in single cells raises new potentials for better understanding the basic processes that underlie embryonic development. To enable single-cell investigations directly in live embryos, new analytical approaches are needed, particularly those that are sensitive, selective, quantitative, robust, and scalable to dif...

In many animals, maternally synthesized mRNAs are critical for primary germ layer formation. In Xenopus, several maternal mRNAs are enriched in the animal blastomere progenitors of the embryonic ectoderm. We previously identified one of these, WW-domain binding protein 2 N-terminal like (wbp2nl), that others previously characterized as a sperm prot...

Many molecular factors required for later stages of neuronal differentiation have been identified; however, much less is known about the early events that regulate the initial establishment of the neuroectoderm. We have used an in vitro embryonic stem cell differentiation model to investigate early events of neuronal differentiation, and to define...

Mutations in SIX1 and in its co-factor, EYA1, underlie Branchiootorenal Spectrum disorder (BOS), which is characterized by variable branchial arch, otic and kidney malformations. However, mutations in these two genes are identified in only half of patients. We screened for other potential co-factors, and herein characterize one of them, Pa2G4 (aka...

Direct measurement of protein expression with single-cell resolution promises to deepen the understanding of the basic molecular processes during normal and impaired development. High-resolution mass spectrometry provides detailed coverage of the proteomic composition of large numbers of cells. Here we discuss recent mass spectrometry developments...

Quantification of protein expression in single cells promises to advance a systems-level understanding of normal development. Using a bottom-up proteomic workflow and multiplexing quantification by tandem mass tags, we recently demonstrated relative quantification between single embryonic cells (blastomeres) in the frog (Xenopus laevis) embryo. In...

The decision by embryonic ectoderm to give rise to epidermal versus neural derivatives is the result of signaling events during blastula and gastrula stages. However, there also is evidence in Xenopus that cleavage stage blastomeres contain maternally derived molecules that bias them toward a neural fate. We used a blastomere explant culture assay...

Single-cell metabolic mass spectrometry enables the discovery (untargeted) analysis of small molecules in individual cells. Using single-cell capillary electrophoresis high-resolution mass spectrometry (CE-HRMS), we recently uncovered small-molecule differences between embryonic cells located along the animal-vegetal and dorsal-ventral axes of the...

We compared apparent origins, cellular diversity and regulation of initial axon growth for differentiating cranial sensory neurons. We assessed the molecular and cellular composition of the developing olfactory and otic placodes, and cranial sensory ganglia to evaluate contributions of ectodermal placode versus neural crest at each site. Special se...

Supplementary

We advance mass spectrometry from a cell population-averaging tool to one capable of quantifying the expression of diverse proteins in single embryonic cells. Our instrument combines capillary electrophoresis (CE), electrospray ionization, and a tribrid ultrahigh-resolution mass spectrometer (HRMS) to enable untargeted (discovery) proteomics with c...

Cranial sensory placodes arise from a common precursor field, the pre-placodal ectoderm (PPE), which surrounds the anterior neural plate just lateral to the neural crest. They give rise to secretory cells and numerous sensory structures in the vertebrate head. The PPE forms in response to interactions between the neural and non-neural ectoderm and...

Pediatric dysphagia-feeding and swallowing difficulties that begin at birth, last throughout childhood, and continue into maturity-is one of the most common, least understood complications in children with developmental disorders. We argue that a major cause of pediatric dysphagia is altered hindbrain patterning during pre-natal development. Such c...

Congenital hearing loss is an important clinical problem because, without early intervention, affected children do not properly acquire language and consequently have difficulties developing social skills. Although most newborns in the US are screened for hearing deficits, even earlier diagnosis can be made with prenatal genetic screening. Genetic...

Significance Spatiotemporal characterization of molecular expression during embryonic development is critical for understanding how cells become different and give rise to distinct tissues and organs. Technological advances enabled the measurement of RNAs and proteins in single cells of embryos, but there is very little information on small molecul...

BMP signaling distinguishes between neural and non-neural fates by activating epidermis-specific transcription and repressing neural-specific transcription. The neural ectoderm forms after the Organizer secrets antagonists that prevent these BMP-mediated activities. However, it is not known whether neural genes also are transcriptionally activated....

Cranial sensory placodes derive from discrete patches of the head ectoderm and give rise to numerous sensory structures. During gastrulation, a specialized "neural border zone" forms around the neural plate in response to interactions between the neural and nonneural ectoderm and signals from adjacent mesodermal and/or endodermal tissues. This zone...

Background Six1 plays an important role in the development of several vertebrate organs, including cranial sensory placodes, somites and kidney. Although Six1 mutations cause one form of Branchio-Otic Syndrome (BOS), the responsible gene in many patients has not been identified; genes that act downstream of Six1 are potential BOS candidates.Results...

Initial interest in understanding how the fertilized egg becomes a multicellular animal suggested two possible answers: either the embryo came from preformed components or it arose through epigenetic processes. Extensive research during the past few decades has identified aspects of development that depend on preformed elements, such as cytoplasmic...

Xenopus laevis eggs are used as a biological model system for studying fertilization and early embryonic development in vertebrates. Most methods used for their molecular analysis require elaborate sample preparation including separate protocols for the water soluble and lipid components. In this study, laser ablation electrospray ionization (LAESI...

The early steps of neural development in the vertebrate embryo are regulated by sets of transcription factors that control the induction of proliferative, pluripotent neural precursors, the expansion of neural plate stem cells, and their transition to differentiating neural progenitors. These early events are critical for producing a pool of multip...

Advances in single cell analysis techniques have demonstrated cell-to-cell variability in both homogeneous and heterogeneous cell populations strengthening our understanding of multicellular organisms and individual cell behaviour. However, additional tools are needed for non-targeted metabolic analysis of live single cells in their native environm...

Specialized sensory organs in the vertebrate head originate from thickenings in the embryonic ectoderm called cranial sensory placodes. These placodes, as well as the neural crest, arise from a zone of ectoderm that borders the neural plate. This zone separates into a precursor field for the neural crest that lies adjacent to the neural plate, and...

Many animals utilize maternal mRNAs to pre-pattern the embryo before the onset of zygotic transcription. In Xenopus laevis, vegetal factors specify the germ line, endoderm and dorsal axis, but there are few studies demonstrating roles for animal-enriched maternal mRNAs. Therefore, we carried out a microarray analysis to identify novel maternal tran...

We assessed feeding-related developmental anomalies in the LgDel mouse model of Chromosome 22q11 Deletion Syndrome (22q11DS), a common developmental disorder that frequently includes perinatal dysphagia - debilitating feeding, swallowing and nutrition difficulties from birth onward - within its phenotypic spectrum. LgDel pups gain significantly les...

THE EARLIEST STEPS OF EMBRYONIC NEURAL DEVELOPMENT ARE ORCHESTRATED BY SETS OF TRANSCRIPTION FACTORS THAT CONTROL AT LEAST THREE PROCESSES: the maintenance of proliferative, pluripotent precursors that expand the neural ectoderm; their transition to neurally committed stem cells comprising the neural plate; and the onset of differentiation of neura...

FoxD4L1 is a forkhead transcription factor that expands the neural ectoderm by down-regulating genes that promote the onset of neural differentiation and up-regulating genes that maintain proliferative neural precursors in an immature state. We previously demonstrated that binding of Grg4 to an Eh-1 motif enhances the ability of FoxD4L1 to down-reg...

Multiple sequence alignments of FoxD4L1 of fish and amphibians. The sequence alignment shows the consensus sequences, conservation and the quality of sequence alignment. The sequences alignments were analyzed by software Jalview 2.8 [66]. (TIF)

Ten statistically significant C-terminal motifs identified with the expectation-maximization algorithm implemented in the MEME program in FoxD4L1 of fish and amphibians [55]. Those indicated by 9–10 sites are found in both frog and fish, whereas those indicted by only 5 sites are amphibian-specific. (TIF)

Multiple sequence alignments of FoxD4/FoxD4L1 of amphibians and mammals. The sequence alignment shows the consensus sequences, conservation and the quality of sequence alignment. The sequences alignments were analyzed by software Jalview 2.8 [66]. (TIF)

Prediction of secondary structure of Xenopus FoxD4L1A using the Network Protein Sequence Analysis server. As a comparison, the secondary structure determined in the crystal structure studies in FoxD3 (Genesis/Hfh2) of the winged helix DNA-binding domain, accession number: 2HFH_A. α-helical structures are shown in underlined bold and β-sheets are in...

Gene and protein accession numbers for vertebrate FoxD4L1. (XLSX)

Ten statistically significant C-terminal motifs identified with the expectation-maximization algorithm implemented in the MEME program in FoxD4/FoxD4L1 of mammals and amphibians [55]. (TIF)

A wheel model of the Leucine (Leu) repeating region of Xenopus FoxD4L1A (aa 313–330) indicated that it may form an amphipathic α-helical structure. (TIF)

Fate maps, constructed from lineage tracing all of the cells of an embryo, reveal which tissues descend from each cell of the embryo. Although fate maps are very useful for identifying the precursors of an organ and for elucidating the developmental path by which the descendant cells populate that organ in the normal embryo, they do not illustrate...