Paul A Overbeek

• PhD
• Professor (Full) at Baylor College of Medicine

While increased mitochondrial reactive oxygen species have been commonly implicated in a variety of disease states, their in vivo role in the pathogenesis of diabetic nephropathy remains controversial. Using a two-photon imaging approach with a genetically encoded redox biosensor, we monitored mitochondrial redox state in the kidneys of experimenta...

Neural tube closure is a critical feature of central nervous system morphogenesis during embryonic development. Failure of this process leads to neural tube defects, one of the most common forms of human congenital defects. Although molecular and genetic studies in model organisms have provided insights into the genes and proteins that are required...

The regulatory roles of long noncoding RNAs (lncRNAs) in transcriptional coactivators are still largely unknown. Here, we have shown that the peroxisome proliferator-activated receptor γ (PPARγ) coactivator α (PGC-1α, encoded by Ppargc1a) is functionally regulated by the lncRNA taurine-upregulated gene 1 (Tug1). Further, we have described a role fo...

After using a self-inactivating lentivirus for non-targeted insertional mutagenesis in mice, we identified a transgenic family with a recessive mutation that resulted in reduced fertility in homozygous transgenic mice. The lentiviral integration site was amplified by inverse PCR. Sequencing revealed that integration had occurred in intron 8 of the...

How the kidney responds to the metabolic cues from the environment remains a central question in kidney research. This question is particularly relevant to the pathogenesis of diabetic nephropathy (DN) in which evidence suggests that metabolic events in podocytes regulate chromatin structure. Here, we show that miR-93 is a critical metabolic/epigen...

Supplementary Figures 1-10 and Supplementary Tables 1 & 2.

Studying embryonic mouse development is important for our understanding of normal human embryogenesis and the underlying causes of congenital defects. Our research focuses on imaging early development in the mouse embryo to specifically understand cardiovascular development using optical coherence tomography (OCT). We have previously developed imag...

In most cases of primary ovarian insufficiency (POI), the cause of the depletion of ovarian follicles is unknown. Fanconi anemia (FA) proteins are known to play important roles in follicular development. Using random insertional mutagenesis with a lentiviral transgene, we identified a family with reduced fertility in the homozygous transgenic mice....

DNA sequencing of the integration site. The junction sequences map to intron 8 of Fance. (TIF)

Follicle numbers at two different ages. (A,B) follicle numbers in 3-week-old ovaries;(C,D) follicle numbers in 5-day-old ovaries. (TIF)

Efficient phenotyping of developmental defects in model organisms is critical for understanding the genetic specification of normal development and congenital abnormalities in humans. We previously reported that optical coherence tomography (OCT) combined with live embryo culture is a valuable tool for mouse embryo imaging and four-dimensional (4-D...

The objective of this study is to determine whether adipose tissue functions as a reservoir for HIV-1. We examined memory CD4 T cells and HIV DNA in adipose tissue-stromal vascular fraction (AT-SVF) of five patients [four antiretroviral therapy (ART)-treated and one untreated]. To determine whether adipocytes stimulate CD4 T cells and regulate HIV...

This chapter provides general advice for investigators who are planning to generate transgenic mice by introduction of new DNA into the mouse genome. It focuses mainly on issues related to mouse husbandry and the establishment of transgenic lines after pronuclear injection of DNA. I discuss trouble-shooting strategies and summarize some common find...

Cohesins are important for chromosome structure and chromosome segregation during mitosis and meiosis. Cohesins are composed of two structural maintenance of chromosomes (SMC1-SMC3) proteins that form a V-shaped heterodimer structure, which is bridged by a a-kleisin protein and a stromal antigen (STAG) protein. Previous studies in mouse have shown...

Cohesins are important for chromosome structure and chromosome segregation during mitosis and meiosis. Cohesins are composed of two structural maintenance of chromosomes (SMC1-SMC3) proteins that form a V-shaped heterodimer structure, which is bridged by a α-kleisin protein and a stromal antigen (STAG) protein. Previous studies in mouse have shown...

Objective:Cleft Palate (CP) is a common birth defect in humans occurring in 6.35/10,000 live births and it has been repeatedly shown that animal models are useful in dissecting molecular etiologies of CP. The OVE1328 mouse line develops CP as a consequence of transgene (Tg) insertion mutagenesis. Preliminary data shows Tg complex integration at chr...

Objectives: Cleft palate (CP) is a common birth defect occurring in 1 in 2000 births. This study investigated a transgene (Tg) insertion mutant mouse line (OVE1226b) which exhibits CP, limb dysplasia, and craniofacial dysmorphology as autosomal recessive traits. Previous work determined that the Tg complex resides in an intergenic region near the 3...

Premature ovarian failure is a major cause of female infertility. The genetic causes of this disorder remain unknown in most patients. Using whole-exome sequence analysis of a large consanguineous family with inherited premature ovarian failure, we identified a homozygous 1-bp deletion inducing a frameshift mutation in STAG3 on chromosome 7. STAG3...

Premature ovarian failure is a major cause of female infertility. The genetic causes of this disorder remain unknown in most patients. Using whole-exome sequence analysis of a large consanguineous family with inherited premature ovarian failure, we identified a homozygous 1-bp deletion inducing a frameshift mutation in STAG3 on chromosome 7. STAG3...

The Notch signaling pathway is thought to regulate multiple stages of inner ear development. Mutations in the Notch signaling pathway cause disruptions in the number and arrangement of hair cells and supporting cells in sensory regions of the ear. In this study we identify an insertional mutation in the mouse Sfswap gene, a putative splicing factor...

Fertilization is the process that leads to the formation of a diploid zygote from two haploid gametes. This is achieved through a complex series of cell-to-cell interactions between a sperm and an egg. The final event of fertilization is the fusion of the gametes' membranes, which allows the delivery of the sperm genetic material into the egg cytop...

Lens induction is a classical embryologic model to study cell fate determination. It has been proposed earlier that specific changes in core histone modifications accompany the process of cell fate specification and determination. The lysine acetyltransferases CBP and p300 function as principal enzymes that modify core histones to facilitate specif...

During wound healing, stem cells provide functional mature cells to meet acute demands for tissue regeneration. Simultaneously, the tissue must maintain a pool of stem cells to sustain its future regeneration capability. However, how these requirements are balanced in response to injury is unknown. Here we demonstrate that after wounding or ultravi...

The FRAS1-related extracellular matrix 1 (FREM1) gene encodes an extracellular matrix protein that plays a critical role in the development of multiple organ systems. In humans, recessive mutations in FREM1 cause eye defects, congenital diaphragmatic hernia, renal anomalies and anorectal malformations including anteriorly placed anus. A similar con...

The FRAS1-related extracellular matrix 1 (FREM1) gene encodes an extracellular matrix protein that plays a critical role in the development of multiple organ systems. In humans, recessive mutations in FREM1 cause eye defects, congenital diaphragmatic hernia, renal anomalies and anorectal malformations including anteriorly placed anus. A similar con...

Congenital ichthyoses are life-threatening conditions in humans. We describe here the identification and molecular characterization of a novel recessive mutation in mice that results in newborn lethality with severe congenital lamellar ichthyosis. Mutant newborns have a taut, shiny, non-expandable epidermis that resembles cornified manifestations o...

Using transposon-mediated gene-trap mutagenesis, we have generated a novel mouse mutant termed Blad (Bloated Bladder). Homozygous mutant mice die perinatally showing a greatly distended bladder, underdeveloped diaphragm and a reduction in total skeletal muscle mass. Wild type and heterozygote mice appear normal. Using PCR, we identified a transposo...

Phenotype of an Nmnat2 gene-trap mouse derived from ES cell clone EUCE0262a08 obtained from the European Conditional Mouse Mutagenesis Program (EUCOMM). A, representative image of a heterozygous Nmnat2+/gt (+/gt) pup and a homozygous Nmnat2gt/gt (gt/gt) pup just after birth (P0). Homozygous Nmnat2gt/gt pups died at birth, due to a failure to initia...

A hybrid piggyBac/Sleeping Beauty transposon-based insertional mutagenesis system that can be mobilized by simple breeding was established in the rat. These transposons were engineered to include gene trap sequences and a tyrosinase (Tyr) pigmentation reporter to rescue the albinism of the genetic background used in the mutagenesis strategy. Single...

Mouse models of ocular diseases provide a powerful resource for exploration of molecular regulation of eye development and pre-clinical studies. Availability of a live high-resolution imaging method for mouse embryonic eyes would significantly enhance longitudinal analyses and high-throughput morphological screening. We demonstrate that optical coh...

Human retinoblastomas form during the proliferative phase of retina development and are caused by mutations that result in absent or functionally defective Rb protein. Similar tumors occur in mice only when multiple Rb gene family members are absent. We asked if retinal tumors can arise from an undifferentiated retinal cell. The tumor-initiating ce...

Objectives: Cleft palate (CP) is a common birth defect occurring in 1 in 2000 live births. CP can be isolated or associated with a recognized syndrome. This study investigated a transgene (Tg) insertion mouse line (OVE1226b) which demonstrates CP, limb dysplasia, and craniofacial dysmorphology as an autosomal recessive trait. Localization of the Tg...

The head bobber transgenic mouse line, produced by pronuclear integration, exhibits repetitive head tilting, circling behavior, and severe hearing loss. Transmitted as an autosomal recessive trait, the homozygote has vestibular and cochlea inner ear defects. The space between the semicircular canals is enclosed within the otic capsule creating a va...

Several lines of evidence suggest that mitochondrial dysfunction plays a critical role in the pathogenesis of microvascular complications of diabetes, including diabetic nephropathy. However, the signaling pathways by which hyperglycemia leads to mitochondrial dysfunction are not fully understood. Here we examined the role of Rho-associated coiled...

Congenital abnormalities of the limbs are common birth defects. These include missing or extra fingers or toes, abnormal limb length, and abnormalities in patterning of bones, cartilage or muscles. Optical Coherence Tomography (OCT) is a 3-D imaging modality, which can produce high-resolution (~8 μm) images of developing embryos with an imaging dep...

Correct development of the cerebellum requires coordinated sonic hedgehog (Shh) signaling from Purkinje to granule cells. How Shh expression is regulated in Purkinje cells is poorly understood. Using a novel tyrosinase minigene-tagged Sleeping Beauty transposon-mediated mutagenesis, which allows for coat color-based genotyping, we created mice in w...

Autism spectrum disorder (ASD) diagnoses are behaviorally based with no defined universal biomarkers, occur at a 1:110 ratio in the population, and predominantly affect males compared to females at approximately a 4:1 ratio. One approach to investigate and identify causes of ASD is to use organisms that display abnormal behavioral responses that mo...

Overloading of unfolded or misfolded proteins in the endoplasmic reticulum (ER) can cause ER stress and activate the unfolded protein response (UPR) in the cell. The authors tested whether transgene overexpression in the mouse lens would activate the UPR. Transgenic mice expressing proteins that either enter the ER secretory pathway or are synthesi...

Abstract Development of the secondary palate in mammals is a complex process that can be easily perturbed, leading to the common and distressing birth defect cleft palate. Animal models are particularly useful tools for dissecting underlying genetic components of cleft palate. We describe a new cleft palate model resulting from a transgene insertio...

Deficiency in the serine protease inhibitor LEKTI is the etiological origin of Netherton syndrome, which causes detachment of the stratum corneum and chronic inflammation. Here we show that the membrane protease matriptase initiates Netherton syndrome in a LEKTI-deficient mouse model by premature activation of a pro-kallikrein cascade. Auto-activat...

We report the generation and initial characterization of a mouse line expressing tamoxifen-inducible improved Cre (iCre) recombinase (iCre-ER(T2)) under the regulation of NPHS2 (podocin) gene promoter. The resulting transgenic mouse line was named podocin-iCreER(T2) mice. The efficiency of iCre activity was confirmed by crossing podocin-iCreER(T2)...

Mammalian Ras genes regulate diverse cellular processes including proliferation and differentiation and are frequently mutated in human cancers. Tumor development in response to Ras activation varies between different tissues and the molecular basis for these variations are poorly understood. The murine lens and cornea have a common embryonic origi...

Transforming growth factor beta (TGFbeta) is an important cytokine in corneal development and wound healing. Transgenic mice that express an active form of human TGFbeta1 driven by a lens-specific promoter were used in the current study to determine the biological effects of lens-derived TGFbeta1 on postnatal corneal development and homeostasis. Th...

Bone morphogenetic proteins (BMPs) play pivotal roles in the regulation of skin development. To study the role of BMPs in skin tumorigenesis, BMP antagonist noggin was used to generate keratin 14-targeted transgenic mice. In contrast to wild-type mice, transgenic mice developed spontaneous hair follicle-derived tumors, which resemble human trichofo...

Wnt/beta-catenin and NF-kappaB signaling mechanisms provide central controls in development and disease, but how these pathways intersect is unclear. Using hair follicle induction as a model system, we show that patterning of dermal Wnt/beta-catenin signaling requires epithelial beta-catenin activity. We find that Wnt/beta-catenin signaling is abso...

Pax6 is a highly conserved transcription factor that controls the morphogenesis of various organs. Changes in Pax6 dosage have been shown to affect the formation of multiple tissues. PAX6 haploinsufficiency leads to aniridia, a pan-ocular disease primarily characterized by iris hypoplasia. Herein, we employ a modular system that includes null and o...

The hair follicles (HFs) and the interfollicular epidermis (IFE) of intact mature skin are maintained by distinct stem cell populations. Upon wounding, however, emigration of HF keratinocytes to the IFE plays a role in acute stages of healing. In addition to this repair function, rapidly cycling cells of the upper HF have been observed transiting t...

Several neurotrophic factors (NTFs) are effective in protecting retinal photoreceptor cells from the damaging effects of constant light and slowing the rate of inherited photoreceptor degenerations. It is currently unclear whether, if continuously available, all NTFs can be protective for many or most retinal degenerations (RDs). We used transgenic...

It is widely accepted that vitreous humor-derived FGFs are required for the differentiation of anterior lens epithelial cells into crystallin-rich fibers. We show that BMP2, 4, and 7 can induce the expression of markers of fiber differentiation in primary lens cell cultures to an extent equivalent to FGF or medium conditioned by intact vitreous bod...

The lens in the vertebrate eye has been shown to be critical for proper differentiation of the surrounding ocular tissues including the cornea, iris and ciliary body. In mice, previous investigators have assayed the consequences of molecular ablation of the lens. However, in these studies, lens ablation was initiated (and completed) after the corne...

Patterning events during early eye formation determine retinal cell fate and can dictate the behavior of retinal ganglion cell (RGC) axons as they navigate toward central brain targets. The temporally and spatially regulated expression of bone morphogenetic proteins (BMPs) and their receptors in the retina are thought to play a key role in this pro...

The mitochondrion is involved in energy generation, apoptosis regulation, and calcium homeostasis. Mutations in genes involved in mitochondrial processes often result in a severe phenotype or embryonic lethality, making the study of mitochondrial involvement in aging, neurodegeneration, or reproduction challenging. Using a transgenic insertional mu...

The retinoblastoma (Rb) gene family member p130 binds preferentially to the E2F5 transcription factor and forms a repressive E2F5/p130 complex that inhibits cell cycle progression and tumor growth. It is unclear whether E2F5, either alone or in combination with p130, can interfere with the transcriptional activity of other E2F family members, such...

A significant barrier to exploiting the full potential of the rat as a biomedical model is the lack of tools to easily modify its germline. Here we show that a tyrosinase-tagged Sleeping Beauty transposon can be used as a simple, efficient method to generate rat mutants in vivo. By making two lines of transgenic rats, one carrying the transposon an...

The purpose of this study was to reassess the role of the lens as an "embryonic organizer" of ocular tissues. We ablated the lens in mice by lens-specific expression of an attenuated version of diphtheria toxin A subunit(Tox176) driven by a modified crystallin promoter. Alterations in the differentiation programs of ocular tissues were examined by...

Insulin and insulin-like growth factors (IGFs) are putative regulators of cell proliferation and differentiation during lens development. Transgenic mice that overexpress IGF-1 in the lens have been previously described. To further understand the ocular functions of this growth factor family, the in vivo effects of insulin expression on lens develo...

The vertebrate ocular lens is a simple and continuously growing tissue. Growth factor-mediated receptor tyrosine kinases (RTKs) are believed to be required for lens cell proliferation, differentiation and survival. The signaling pathways downstream of the RTKs remain to be elucidated. Here, we demonstrate the important role of Ras in lens developme...

Smad3, a mediator of TGF-beta signaling has been shown to be involved in the epithelial-to-mesenchymal transformation (EMT) of lens epithelial cells in a lens injury model. In this study, the role of Smad3 in anterior subcapsular cataract (ASC) formation was investigated in a transgenic TGF-beta/Smad3 knockout mouse model. TGF-beta1 transgenic mice...

Hair follicles are spaced apart from one another at regular intervals through the skin. Although follicles are predominantly epidermal structures, classical tissue recombination experiments indicated that the underlying dermis defines their location during development. Although many molecules involved in hair follicle formation have been identified...

In this study, we used laser capture microdissection (LCM) and microarray hybridization technology to compare the gene expression profiles of mouse embryonic days 10 and 12 lenses (E10 and E12). Lens cells of C57/BL6 mouse embryos at E10 and E12 were harvested using the PixCell II LCM System. Total RNA was extracted, amplified, labeled, and hybridi...

The flat bones of the skull (i.e., the frontal and parietal bones) normally form through intramembranous ossification. At these sites cranial mesenchymal cells directly differentiate into osteoblasts without the formation of a cartilage intermediate. This type of ossification is distinct from endochondral ossification, a process that involves initi...

Activating ligands of gp130, including leukemia inhibitory factor (LIF), can block differentiation and function of retinal neurons. This study focused on determining whether LIF inhibits differentiation of photoreceptors by altering cell fate or by blocking the expression of essential transcription factors in vivo. Transgenic mice were generated th...

The purpose of this study was to establish a GAL4/VP16-based binary transactivation system that was active in the lens and corneal epithelium of transgenic mice. We generated transgenic mice with the transcriptional transactivator GAL4/VP16 driven by a modified Pax6 promoter that is active in lens and corneal epithelial cells. We also generated and...

Both the -366/+43 and the -282/+43 mouse alphaA-crystallin (or alphaA) promoters have been effective at driving transgene expression in lens fiber cells, but not in lens epithelium. Because the chick delta1-crystallin gene is expressed in lens epithelial cells, an enhancer was borrowed from this gene and linked to the alphaA promoter. This heteroge...

Netherton syndrome (NS) is a human autosomal recessive skin disease caused by mutations in the SPINK5 gene, which encodes the putative proteinase inhibitor LEKTI. We have generated a transgenic mouse line with an insertional mutation that inactivated the mouse SPINK5 ortholog. Mutant mice exhibit fragile stratum corneum and perinatal death due to d...

Cystic kidney disease has been linked to mutations in the Invs gene in mice with inversion of embryonic turning (inv/inv) and the INVS (NPHP2) gene in infants with nephronophthisis type 2 (NPHP2). The inv mouse model features multiorgan defects including renal cysts, altered left-right laterality, and hepatobiliary duct malformations transmitted in...

Although the murine alphaA-crystallin promoter is the most commonly used promoter for achieving transgene expression in the developing lens, this promoter directs transgene expression efficiently only in lens fiber cells. The purpose of the present study was to generate promoters capable of directing transgene expression to the entire lens but not...

The Odd Sex mouse mutation arose in a transgenic line of mice carrying a tyrosinase minigene driven by the dopachrome tautomerase (Dct) promoter region. The minigene integrated 0.98 Mb upstream of Sox9 and was accompanied by a deletion of 134 kb. This mutation causes female to male sex reversal in XX Ods/+ mice, and a characteristic eye phenotype o...

Mutations in members of the ectodysplasin (TNF-related) signalling pathway, EDA, EDAR, and EDARADD in mice and humans produce an ectodermal dysplasia phenotype that includes missing teeth and smaller teeth with reduced cusps. Using the keratin 14 promoter to target expression of an activated form of Edar in transgenic mice, we show that expression...

Simian virus (SV) 40 large T antigen can both induce tumors and inhibit cellular differentiation. It is not clear whether these cellular changes are synonymous, sequential, or distinct responses to the protein. T antigen is known to bind to p53, to the retinoblastoma (Rb) family of tumor suppressor proteins, and to other cellular proteins such as p...

Inactivation of the retinoblastoma gene in human retinoblasts or mouse lens fiber cells causes inappropriate cell cycle entry, presumably as a consequence of elevated activity of the E2F transcription factors. Although E2Fs are known to be critical regulators of the cell cycle, it is still unclear whether family members E2F3a, E2F4 or E2F5 are indi...

Growth factor signaling is implicated in the regulation of lens cell proliferation and differentiation during development. Activation of growth factor receptor tyrosine kinases is known to activate Ras proteins, small GTP-binding proteins that function as part of the signal transduction machinery. In the present study, we examined which classical R...

The ciliary body in the eye secretes aqueous humor and glycoproteins of the vitreous body and maintains the intraocular pressure. The ciliary muscle controls the shape of the lens through the ciliary zonules to focus the image onto the retina. During embryonic development, the ciliary epithelium is derived from the optic vesicle, but the molecular...

In mammals the SRY gene functions as a dominant genetic switch for testis determination (Gubbay et al.: Nature 346:1128-1135, 1990; Koopman et al.: Nature 351:117-121, 1991; Sinclair et al.: Nature 346:240-244, 1990). To study SRY transcriptional regulation within an evolutionary context, we have generated transgenic mice that express green fluores...

Although some of the transcription factors that are required for expression of crystallins during lens development have been identified, the molecular interactions that contribute to enhanced crystallin expression are not yet well defined. In this study, we designed experiments to test whether the co-activators CREB-binding protein (CBP) and/or p30...

Cadherins are a family of Ca(2+)-dependent cell adhesion molecules. Through their homophilic binding interactions, cadherins play important roles in tissue formation and maintenance during development. Here the authors compare the expression patterns of the three classical cadherins, E-, N- and P-cadherin, during mouse eye development from embryoni...

Formation of the neural tube plays a primary role in establishing the body plan of the vertebrate embryo. Here we describe the phenotype and physical mapping of a highly penetrant X-linked male-lethal murine mutation, exma (exencephaly, microphthalmia/anophthalmia), that specifically disrupts development of the rostral neural tube and eye. The muta...

The alphaA-crystallin promoter was used to target expression of bone morphogenetic protein 7 (BMP7) to lens fiber cells in transgenic mice. Surprisingly, lens-specific expression of BMP7 induced widespread apoptosis and rapid ablation of the neural retina in multiple families. Subsequent to retinal ablation, the lens bow region shifted posteriorly...