Biomedical subjects

Lisa D White

Publications and source records attributed to Lisa D White.

7 recordsLinked to original sources

PubMed2006

Gene expression profiling in embryonic mouse lenses.

PURPOSE: 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). METHODS: 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 hybridized to the 430 2.0 mouse chip (Affymetrix) according to the manufacturer's instructions. Data extracted from the images were analyzed using different software programs. Regulated expression of selected genes was confirmed by real-time PCR (RT-PCR). RESULTS: Analysis of the microarray data from E10 and E12 lenses identified 1,573 genes that showed a two fold or greater change in expression level. Among these 1,573 genes, 956 genes were downregulated and 617 were upregulated in E12 lenses. In addition to the upregulated expression of beta- and gamma-crystallin genes, genes that regulate the cell cycle showed significant changes of gene expression during the E10 (lens pit) to E12 (primary fiber cell induction) time period. Genes involved in insulin-like growth factor (IGF) signaling and Wnt (a family of secreted glycoproteins related to the Drosophila segment polarity gene, wingless, and to the proto-oncogene, int-1) signaling were also differentially regulated. In particular, positive regulators of Wnt signaling were downregulated and negative regulators were upregulated, indicating that modulation of Wnt signaling is important for normal lens morphogenesis. CONCLUSIONS: Our results provide new information about differential regulation of gene expression during early lens development. Analysis of global gene expression profiles in embryonic mouse lenses has allowed us to identify several molecular pathways that are differentially regulated during early lens development.

Animals↗

PubMed2006

Reactivation of developmentally expressed p63 isoforms predisposes to tumor development and progression.

Genes that are active during normal development are frequently reactivated during neoplastic transformation. We now report that developmentally expressed TAp63 isoforms are frequently reactivated in human squamous cell carcinomas. To determine the consequences of TAp63 reactivation, we induced TAp63alpha expression during chemically-induced skin carcinogenesis. Deregulated TAp63alpha expression dramatically accelerated tumor development and progression, frequently resulting in epithelial-mesenchymal transitions to spindle cell carcinomas and lung metastases. Consistent with this observation, we detected high levels of Twist and N-cadherin in tumors overexpressing TAp63alpha. Thus, as observed for other developmental pathways, aberrant reactivation of TAp63 predisposes to tumor development and progression.

Animals↗

PubMed2006

Dominant-stable beta-catenin expression causes cell fate alterations and Wnt signaling antagonist expression in a murine granulosa cell tumor model.

Wnt/beta-catenin signaling is normally involved in embryonic development and tissue homeostasis, and its misregulation leads to several forms of cancer. We have reported that misregulated Wnt/beta-catenin signaling occurs in ovarian granulosa cell tumors (GCT) and have created the Catnb(flox(ex3)/+);Amhr2(cre/+) mouse model, which expresses a dominant-stable mutant of beta-catenin in granulosa cells and develops late-onset GCT. To study the mechanisms leading to GCT development, gene expression analysis was done using microarrays comparing Catnb(flox(ex3)/+);Amhr2(cre/+) ovaries bearing pretumoral lesions with control ovaries. Overexpressed genes identified in Catnb(flox(ex3)/+);Amhr2(cre/+) ovaries included the Wnt/beta-catenin signaling antagonists Wif1, Nkd1, Dkk4, and Axin2, consistent with the induction of negative feedback loops that counteract uncontrolled Wnt/beta-catenin signaling. Expression of the antagonists was localized to cells forming the pretumoral lesions but not to normal granulosa cells. Microarray analyses also revealed the ectopic expression of bone markers, including Ibsp, Cdkn1c, Bmp4, and Tnfrsf11b, as well as neuronal/neurosecretory cell markers, such as Cck, Amph, Pitx1, and Sp5. Increased expression of the gene encoding the cytokine pleiotrophin was also found in Catnb(flox(ex3)/+);Amhr2(cre/+) ovaries and GCT but was not associated with increased serum pleiotrophin levels. In situ hybridization analyses using GCT from Catnb(flox(ex3)/+);Amhr2(cre/+) mice revealed that Wnt/beta-catenin antagonists and neuronal markers localized to a particular cell population, whereas the bone markers localized to a distinct cell type associated with areas of osseous metaplasia. Together, these results suggest that misregulated Wnt/beta-catenin signaling alters the fate of granulosa cells and that the GCT that arise in Catnb(flox(ex3)/+);Amhr2(cre/+) mice result from the clonal expansion of metaplastic cells.

Adaptor Proteins, Signal Transducing↗

PubMed2006

The genomic analysis of the impact of steroid receptor coactivators ablation on hepatic metabolism.

Members of the steroid receptor coactivator (SRC) family, which include SRC-1 (NcoA-1/p160), SRC-2(TIF2/GRIP1/NcoA-2) and SRC-3(pCIP/RAC3/ACTR/pCIP/ AIB1/TRAM1), are critical mediators of steroid receptor action. Gene ablation studies previously identified SRC-1 and SRC-2 as being involved in the control of energy homeostasis. A more precise identification of the molecular pathways regulated by these coactivators is crucial for understanding the role of steroid receptor coactivators in the control of energy homeostasis and obesity. A genomic approach using microarray analysis was employed to identify the subsets of genes that are altered in the livers of SRC-1-/-, SRC-2-/-, and SRC-3-/- mice. Microarray analysis demonstrates that gene expression changes are specific and nonoverlapping for each SRC member in the liver. The overall pattern of altered gene expressions in the SRC-1-/- mice was up-regulation, whereas SRC-2-/- mice showed an overall down-regulation. Several key regulatory enzymes of energy metabolism were significantly altered in the liver of SRC-2-/- mice, which are consistent with the prior observation that SRC-2-/- mice have increased energy expenditure. This study demonstrates that the molecular targets of SRC-2 regulation in the murine liver stimulate fatty acid degradation and glycolytic pathway, whereas fatty acid, cholesterol, and steroid biosynthetic pathways are down-regulated.

Animals↗

PubMed2005

Spectrum of CHD7 mutations in 110 individuals with CHARGE syndrome and genotype-phenotype correlation.

CHARGE syndrome is a well-established multiple-malformation syndrome with distinctive consensus diagnostic criteria. Characteristic associated anomalies include ocular coloboma, choanal atresia, cranial nerve defects, distinctive external and inner ear abnormalities, hearing loss, cardiovascular malformations, urogenital anomalies, and growth retardation. Recently, mutations of the chromodomain helicase DNA-binding protein gene CHD7 were reported to be a major cause of CHARGE syndrome. We sequenced the CHD7 gene in 110 individuals who had received the clinical diagnosis of CHARGE syndrome, and we detected mutations in 64 (58%). Mutations were distributed throughout the coding exons and conserved splice sites of CHD7. Of the 64 mutations, 47 (73%) predicted premature truncation of the protein. These included nonsense and frameshift mutations, which most likely lead to haploinsufficiency. Phenotypically, the mutation-positive group was more likely to exhibit cardiovascular malformations (54 of 59 in the mutation-positive group vs. 30 of 42 in the mutation-negative group; P=.014), coloboma of the eye (55 of 62 in the mutation-positive group vs. 30 of 43 in the mutation-negative group; P=.022), and facial asymmetry, often caused by seventh cranial nerve abnormalities (36 of 56 in the mutation-positive group vs. 13 of 39 in the mutation-negative group; P=.004). Mouse embryo whole-mount and section in situ hybridization showed the expression of Chd7 in the outflow tract of the heart, optic vesicle, facio-acoustic preganglion complex, brain, olfactory pit, and mandibular component of the first branchial arch. Microarray gene-expression analysis showed a signature pattern of gene-expression differences that distinguished the individuals with CHARGE syndrome with CHD7 mutation from the controls. We conclude that cardiovascular malformations, coloboma, and facial asymmetry are common findings in CHARGE syndrome caused by CHD7 mutation.

Abnormalities, Multiple↗

PubMed2005

Identification of murine uterine genes regulated in a ligand-dependent manner by the progesterone receptor.

Progesterone (P4) acting through its cognate receptor, the progesterone receptor (PR), plays an important role in uterine physiology. The PR knockout (PRKO) mouse has demonstrated the importance of the P4-PR axis in the regulation of uterine function. To define the molecular pathways regulated by P4-PR in the mouse uterus, Affymetrix MG U74Av2 oligonucleotide arrays were used to identify alterations in gene expression after acute and chronic P4 treatments. PRKO and wild-type mice were ovariectomized and then treated with vehicle or 1 mg P4 every 12 h. Mice were killed either 4 h after the first injection (acute P4 treatment) or after the fourth injection of P4 (chronic P4 treatment). At the genomic level, the major change in gene expression after acute P4 treatment was an increase in the expression of 55 genes. Conversely, the major change in gene expression after chronic P4 treatment was an overall reduction in the expression of 102 genes. In the analysis, retinoic acid metabolic genes, cytochrome P 450 26a1 (Cyp26a1), alcohol dehydrogenase 5, and aldehyde dehydrogenase 1a1 (Aldh1a1); kallikrein genes, Klk5 and Klk6; and specific transcription factors, GATA-2 and Cited2 [cAMP-corticosterone-binding protein/p300-interacting transactivator with glutamic acid (E) and aspartic acid (D)-rich tail], were validated as regulated by the P4-PR axis. Identification and analysis of these responsive genes will help define the role of PR in regulating uterine biology.

Animals↗

PubMed2003

Development of a comparative genomic hybridization microarray and demonstration of its utility with 25 well-characterized 1p36 deletions.

Chromosomal abnormalities, such as deletions and duplications, are characterized by specific and often complex phenotypes resulting from an imbalance in normal gene dosage. However, routine chromosome banding is not sensitive enough to detect subtle chromosome aberrations (<5-10 Mb). Array-based comparative genomic hybridization (array CGH) is a powerful new technology capable of identifying chromosomal imbalance at a high resolution by co-hybridizing differentially labeled test and control DNAs to a microarray of genomic clones. We used a previously assembled contig of large-insert clones that span 10.5 Mb of the most distal region of 1p36 to design a microarray. The array includes 97 clones from 1p36, 41 clones from the subtelomeric regions of all human chromosomes, and three clones from each of the X and Y chromosomes. We used this microarray to study 25 subjects with well-characterized deletions of 1p36. All array CGH results agree with the deletion sizes and locations of the breakpoints in these subjects as determined previously by FISH and microsatellite analyses. Terminal deletions, interstitial deletions, derivative chromosomes and complex rearrangements were also identified. We anticipate that array CGH will change the diagnostic approach to many congenital and acquired genetic diseases such as mental retardation, birth defects and cancer.

Chromosome Aberrations↗