Transcriptome from opaque cornea of Fanconi anemia patient uncovers fibrosis and two connected players.

Congenital corneal opacities (CCO) are a group of blinding corneal disorders, where the underlying molecular mechanisms are poorly understood. Phenotyping through specialized imaging and histopathology analysis, together with assessment of key transcriptomic changes (including glycosaminoglycan metabolic enzymes) in cornea(s) with CCO from a case of Fanconi anemia is the approach taken in this study to identify causal mechanisms. Based on our findings, we propose a novel mechanism and two key players contributing to CCO.

Clinical and imaging characteristics of posterior column ataxia with retinitis pigmentosa with a specific FLVCR1 mutation.

Background: Posterior column ataxia retinitis pigmentosa (PCARP) with feline leukemia virus subgroup C cellular receptor 1 (FLVCR1) gene mutation is a rare disorder with significant ophthalmic features.

Materials And Methods: We conducted a retrospective case series study of patients diagnosed with PCARP and genetic testing positive for FLVCR1 mutation between 1 January 2015 and 1 October 2017 at the Children's Hospital of Pittsburgh. Clinical charts, visual fields, fundus autofluorescence, and spectral-domain optical coherence tomography (SD-OCT) were reviewed.

Case series: Pyramidal cataracts, intact irides and nystagmus from three novel mutations.

Purpose: To investigate the association between novel mutations to bilateral anterior pyramidal congenital cataracts (APyC), complete and intact irides, and nystagmus.

Observations: This is a retrospective observational case series in a multi-center setting with genetic testing. Three female patients were diagnosed with bilateral APyC, intact irides and nystagmus.

Subterranean mammals show convergent regression in ocular genes and enhancers, along with adaptation to tunneling.

The underground environment imposes unique demands on life that have led subterranean species to evolve specialized traits, many of which evolved convergently. We studied convergence in evolutionary rate in subterranean mammals in order to associate phenotypic evolution with specific genetic regions. We identified a strong excess of vision- and skin-related genes that changed at accelerated rates in the subterranean environment due to relaxed constraint and adaptive evolution.

Congenital aniridia: etiology, manifestations and management.

Congenital aniridia manifests as total or partial absence of the iris caused most commonly by mutations in PAX6, FOXC1, PITX2, and CYP1B1. Recently two new genes, and , have also been implicated in isolated studies. We discuss the genotype-phenotype correlations for the main implicated genes.

Isolated Sagittal Synostosis in a Boy with Craniofrontonasal Dysplasia and a Novel EFNB1 Mutation.

Craniofrontonasal syndrome (CFNS) is a rare X-linked disorder that shows greater severity in females and is largely attributed to mutations in EFNB1. A 7-year-old boy presented with hypertelorism, broad nasal root, midfacial hypoplasia, mandibular prognathia, ptosis, and scaphocephaly was clinically diagnosed with CFNS. Three-dimensional computed tomographic scans confirmed the isolated sagittal synostosis.

A Trio-RhoA-Shroom3 pathway is required for apical constriction and epithelial invagination.

Epithelial invagination is a common feature of embryogenesis. An example of invagination morphogenesis occurs during development of the early eye when the lens placode forms the lens pit. This morphogenesis is accompanied by a columnar-to-conical cell shape change (apical constriction or AC) and is known to be dependent on the cytoskeletal protein Shroom3.

Balanced Rac1 and RhoA activities regulate cell shape and drive invagination morphogenesis in epithelia.

Epithelial bending is a central feature of morphogenesis in animals. Here we show that mutual antagonism by the small Rho GTPases Rac1 and RhoA determines cell shape, tissue curvature, and invagination activity in the model epithelium of the developing mouse lens. The epithelial cells of the invaginating lens placode normally elongate and change from a cylindrical to an apically constricted, conical shape.

Rac1 GTPase-deficient mouse lens exhibits defects in shape, suture formation, fiber cell migration and survival.

Morphogenesis and shape of the ocular lens depend on epithelial cell elongation and differentiation into fiber cells, followed by the symmetric and compact organization of fiber cells within an enclosed extracellular matrix-enriched elastic capsule. The cellular mechanisms orchestrating these different events however, remain obscure. We investigated the role of the Rac1 GTPase in these processes by targeted deletion of expression using the conditional gene knockout (cKO) approach.

Loss of RhoA in neural progenitor cells causes the disruption of adherens junctions and hyperproliferation.

The organization of neural progenitors in the developing mammalian neuroepithelium is marked by cadherin-based adherens junctions. Whereas RhoA, a founding member of the small Rho GTPase family, has been shown to play important roles in epithelial adherens junctions, its physiological roles in neural development remain uncertain due to the lack of specific loss-of-function studies. Here, we show that RhoA protein accumulates at adherens junctions in the developing mouse brain and colocalizes to the cadherin-catenin complex.

RhoA GTPase is dispensable for actomyosin regulation but is essential for mitosis in primary mouse embryonic fibroblasts.

RhoA, the founding member of mammalian Rho GTPase family, is thought to be essential for actomyosin regulation. To date, the physiologic function of RhoA in mammalian cell regulation has yet to be determined genetically. Here we have created RhoA conditional knock-out mice.

Chromatin remodeling enzyme Brg1 is required for mouse lens fiber cell terminal differentiation and its denucleation.

Background: Brahma-related gene 1 (Brg1, also known as Smarca4 and Snf2β) encodes an adenosine-5'-triphosphate (ATP)-dependent catalytical subunit of the (switch/sucrose nonfermentable) (SWI/SNF) chromatin remodeling complexes. SWI/SNF complexes are recruited to chromatin through multiple mechanisms, including specific DNA-binding factors (for example, heat shock transcription factor 4 (Hsf4) and paired box gene 6 (Pax6)), chromatin structural proteins (for example, high-mobility group A1 (HMGA1)) and/or acetylated core histones. Previous studies have shown that a single amino acid substitution (K798R) in the Brg1 ATPase domain acts via a dominant-negative (dn) mechanism.

Cdc42- and IRSp53-dependent contractile filopodia tether presumptive lens and retina to coordinate epithelial invagination.

The vertebrate lens provides an excellent model with which to study the mechanisms required for epithelial invagination. In the mouse, the lens forms from the head surface ectoderm. A domain of ectoderm first thickens to form the lens placode and then invaginates to form the lens pit.

Regulation of alphaA-crystallin via Pax6, c-Maf, CREB and a broad domain of lens-specific chromatin.

Pax6 and c-Maf regulate multiple stages of mammalian lens development. Here, we identified novel distal control regions (DCRs) of the alphaA-crystallin gene, a marker of lens fiber cell differentiation induced by FGF-signaling. DCR1 stimulated reporter gene expression in primary lens explants treated with FGF2 linking FGF-signaling with alphaA-crystallin synthesis.

Palm is expressed in both developing and adult mouse lens and retina.

Background: Paralemmin (Palm) is a prenyl-palmitoyl anchored membrane protein that can drive membrane and process formation in neurons. Earlier studies have shown brain preferred Palm expression, although this protein is a major water insoluble protein in chicken lens fiber cells and the Palm gene may be regulated by Pax6.

Methods: The expression profile of Palm protein in the embryonic, newborn and adult mouse eye as well as dissociated retinal neurons was determined by confocal immunofluorescence.

Ectopic norrin induces growth of ocular capillaries and restores normal retinal angiogenesis in Norrie disease mutant mice.

Norrie disease is an X-linked retinal dysplasia that presents with congenital blindness, sensorineural deafness, and mental retardation. Norrin, the protein product of the Norrie disease gene (NDP), is a secreted protein of unknown biochemical function. Norrie disease (Ndp(y/-)) mutant mice that are deficient in norrin develop blindness, show a distinct failure in retinal angiogenesis, and completely lack the deep capillary layers of the retina.

Regulation of gene expression by Pax6 in ocular cells: a case of tissue-preferred expression of crystallins in lens.

Lens development is an excellent model for genetic and biochemical studies of embryonic induction, cell cycle regulation, cellular differentiation and signal transduction. Differentiation of lens is characterized by lens-preferred expression and accumulation of water-soluble proteins, crystallins. Crystallins are required for light transparency, refraction and maintenance of lens integrity.

Transcriptional regulation of mouse alphaB- and gammaF-crystallin genes in lens: opposite promoter-specific interactions between Pax6 and large Maf transcription factors.

Mammalian alphaB-crystallin is highly expressed both in lens epithelium and lens fibers. In contrast, gammaF-crystallin is highly expressed in the lens fiber cells. Crystallin gene expression in lens is regulated at the level of transcription by a sparse number of specific DNA-binding transcription factors.

Functional interactions between alternatively spliced forms of Pax6 in crystallin gene regulation and in haploinsufficiency.

Pax6 is essential for development of the eye, olfactory system, brain and pancreas. Haploinsufficiency of Pax6 causes abnormal eye development. Two forms of Pax6 protein, PAX6 and PAX6(5a), differ in a 14 amino acid insertion encoded by an alternatively spliced exon 5a in the N-terminal DNA-binding paired domain (PD), and they are simultaneously expressed.

Functional properties of natural human PAX6 and PAX6(5a) mutants.

Purpose: Pax6 is essential for development of the eye, brain, and pancreas. Two major products of PAX6 are specific DNA-binding proteins, PAX6 and PAX6(5a). PAX6(5a) contains a short insertion influencing its DNA-binding activity.

Spectrum and range of oxidative stress responses of human lens epithelial cells to H2O2 insult.

Purpose: Oxidative stress (OS) is believed to be a major contributor to age-related cataract and other age-related diseases.

Methods: cDNA microarrays were used to identify the spectrum and range of genes with transcript levels that are altered in response to acute H(2)O(2)-induced OS in human lens epithelial (HLE) cells. HLE cells were treated with 50 microM H(2)O(2) for 1 hour in the absence of serum, followed by a return to complete medium.

A comparative cDNA microarray analysis reveals a spectrum of genes regulated by Pax6 in mouse lens.

Background: Pax6 is a transcription factor that is required for induction, growth, and maintenance of the lens; however, few direct target genes of Pax6 are known.

Results: In this report, we describe the results of a cDNA microarray analysis of lens transcripts from transgenic mice over-expressing Pax6 in lens fibre cells in order to narrow the field of potential direct Pax6 target genes. This study revealed that the transcript levels were significantly altered for 508 of the 9700 genes analysed, including five genes encoding the cell adhesion molecules beta1-integrin, JAM1, L1 CAM, NCAM-140 and neogenin.

Identification of differentially expressed genes in mouse Pax6 heterozygous lenses.

Purpose: Pax6 is a critical regulator of the developing lens, other ocular tissues, central nervous system, and pancreas. Downstream targets of Pax6 are largely unknown. The present study was designed to identify differentially expressed genes in Pax6 heterozygous and normal mouse lenses.

Cataract- and lens-specific upregulation of ARK receptor tyrosine kinase in Emory mouse cataract.

Purpose: The Emory mouse is a well-characterized model for age-onset cataract. The purpose of the present study was to identify differentially expressed genes between pre- and postcataract Emory mouse lenses.

Methods: Eyes were extracted from Emory mice at 3 weeks (precataract) and 7.

Identification of genes downstream of Pax6 in the mouse lens using cDNA microarrays.

Pax6 is a transcription factor that regulates the development of the visual, olfactory, and central nervous systems, pituitary, and pancreas. Pax6 is required for induction, growth, and maintenance of the lens; however, few direct Pax6 target genes are known. This study was designed to identify batteries of differentially expressed genes in three related systems: 8-week old Pax6 heterozygous lenses, 8-week old Pax6 heterozygous eyes, and transgenic lenses overexpressing PAX6(5a), using high throughput cDNA microarrays containing about 9700 genes.