| 1. |
- Gustafsson, Renata, et al.
(författare)
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Gene expression profiling of differentiating embryonic stem cells expressing dominant negative fibroblast growth factor receptor 2.
- 2007
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Ingår i: Matrix Biology. - : Elsevier BV. - 1569-1802 .- 0945-053X. ; 26, s. 197-205
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Tidskriftsartikel (refereegranskat)abstract
- Embryonic stein (ES) cells are derived from the inner cell mass of the blastocyst and can be cultured as three-dimensional embryoid bodies (EBs) in which embryonic pregastrulation stages are faithfully mimicked. Fibroblast growth factor receptors (mainly FGFR2) are involved in the first differentiation events during early mammalian embryogenesis. It has been demonstrated that the presence of FGFR2 is a prerequisite for laminin-111 and collagen type IV synthesis and subsequently basement membrane formation in EBs. To identify genes that are influenced by FGFR signalling, we performed global gene expression profiling of differentiating EBs expressing dominant negative FGFR2 (dnFGFR2), acquiring an extensive catalogue of down- and up-regulated genes. We show a strong down-regulation of endodermal and basement membrane related genes, which strengthen the view that the FGFR signalling pathway is a main stimulator of basement membrane synthesis in EBs. We further present down-regulation of genes previously not linked to FGFR signalling, and in addition an active transcription of some mesodermal related genes in differentiating dnFGFR2 EBs.
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| 2. |
- Olsson, Magnus, et al.
(författare)
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Nulp1, a novel basic helix-loop-helix protein expressed broadly during early embryonic organogenesis and prominently in developing dorsal root ganglia.
- 2002
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Ingår i: Cell and Tissue Research. - : Springer Science and Business Media LLC. - 1432-0878 .- 0302-766X. ; 308:3, s. 361-370
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Tidskriftsartikel (refereegranskat)abstract
- The basic helix-loop-helix (bHLH) proteins control differentiation and development of a variety of organs. We have isolated the complementary DNA (cDNA) of a novel class of bHLH transcription factors. The previously uncharacterized bHLH messenger RNA (mRNA) was identified by RNA fingerprinting by comparing embryonic and adult mRNA. The reading frame sequence predicts a new class of bHLH family. Northern blotting of embryonic stages demonstrated a 3.2-kb transcript present in several embryonic tissues, including kidney, brain, heart, and lung, in a fashion confirmatory with the RNA-fingerprinting data. In situ hybridization of cryosections detected strong signals in the dorsal root ganglia of 14-day-old mouse embryos (E14). Transient transfection of human embryonic kidney cells with Nulp1-EGFP demonstrated nuclear localization. The complex expression pattern and unique protein sequence, including an acidic amino terminal and putative transcription activation domain, suggests that Nulp1 may have a distinct role in embryonic development of many organs, including the adult brain.
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| 3. |
- Askmyr, Maria, et al.
(författare)
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Low-dose busulphan conditioning and neonatal stem cell transplantation preserves vision and restores hematopoiesis in severe murine osteopetrosis.
- 2009
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Ingår i: Experimental Hematology. - : Elsevier BV. - 1873-2399 .- 0301-472X. ; 37, s. 302-308
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVE: Infantile malignant osteopetrosis is a fatal disease caused by lack of functional osteoclasts. In most of patients, TCIRG1, encoding a subunit of a proton pump essential for bone resorption, is mutated. Osteopetrosis leads to bone marrow failure and blindness due to optic nerve compression. Oc/oc mice have a deletion in Tcirg1 and die around 3 to 4 weeks, but can be rescued by neonatal stem cell transplantation (SCT) after irradiation conditioning. However, as irradiation of neonatal mice results in retinal degeneration, we wanted to investigate whether conditioning with busulphan prior to SCT can lead to preservation of vision and reversal of osteopetrosis in the oc/oc mouse model. MATERIALS AND METHODS: Pregnant dams were conditioned with busulphan and their litters transplanted with 1 x 10(6) normal lineage-depleted bone marrow cells intravenously or intraperitoneally. Mice were followed in terms of survival and engraftment level, as well as with peripheral blood lineage analysis, bone and eye histopathology and a visual-tracking drum test to assess vision. RESULTS: Busulphan at 15 mg/kg was toxic to oc/oc mice. However, six of seven oc/oc mice conditioned with busulphan 7.5 mg/kg survived past the normal lifespan with 10% engraftment, correction of the skeletal phenotype, and normalization of peripheral blood lineages. Busulphan, in contrast to irradiation, did not have adverse effects on the retina as determined by histopathology, and 8 weeks after transplantation control and oc/oc mice retained their vision. CONCLUSION: Low-dose busulphan conditioning and neonatal SCT leads to prolonged survival of oc/oc mice, reverses osteopetrosis and prevents blindness even at low engraftment levels.
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| 4. |
- Charles, Michael A, et al.
(författare)
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PITX genes are required for cell survival and Lhx3 activation.
- 2005
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Ingår i: Molecular Endocrinology. - : The Endocrine Society. - 0888-8809 .- 1944-9917. ; 19:7, s. 1893-1903
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Tidskriftsartikel (refereegranskat)abstract
- The PITX family of transcription factors regulate the development of many organs. Pitx1 mutants have a mild pituitary phenotype, but Pitx2 is necessary for the development of Rathke's pouch, expression of essential transcription factors in gonadotropes, and expansion of the Pit1 lineage. We report that lack of Pitx2 causes the pouch to undergo excessive cell death, resulting in severe pituitary hypoplasia. Transgenic overexpression of PITX2 in the pituitary can increase the gonadotrope population, suggesting that the absolute concentration of PITX2 is important for normal pituitary cell lineage expansion. We show that PITX1 and PITX2 proteins are present in similar expression patterns throughout pituitary development and in the mature pituitary. Both transcription factors are preferentially expressed in adult gonadotropes and thyrotropes, suggesting the possibility of overlap in maintenance of adult pituitary functions within these cell types. Double knockouts of Pitx1 and Pitx2 exhibit severe pituitary hypoplasia and fail to express the transcription factor LHX3. This indicates that these PITX genes are upstream of Lhx3 and have compensatory roles during development. Thus, the combined dosage of these PITX family members is vital for pituitary development, and their persistent coexpression in the adult pituitary suggests a continued role in maintenance of pituitary function.
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| 5. |
- Enjin, Anders, et al.
(författare)
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Identification of novel spinal cholinergic genetic subtypes disclose Chodl and Pitx2 as markers for fast motor neurons and partition cells
- 2010
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Ingår i: Journal of Comparative Neurology. - : Wiley. - 0021-9967 .- 1096-9861. ; 518:12, s. 2284-2304
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Tidskriftsartikel (refereegranskat)abstract
- Spinal cholinergic neurons are critical for motor function in both the autonomic and somatic nervous systems and are affected in spinal cord injury and in diseases such as amyotrophic lateral sclerosis (ALS) and spinal muscular atrophy. Using two screening approaches and in situ hybridization, we identified 159 genes expressed in typical cholinergic patterns in the spinal cord. These include two general cholinergic neuron markers, one gene exclusively expressed in motor neurons and nine genes expressed in unknown subtypes of somatic motor neurons. Further, we present evidence that Chondrolectin (Chodl) is a novel genetic marker for putative fast motor neurons and that estrogen-related receptor b (ERRb) is a candidate genetic marker for slow motor neurons. In addition, we suggest paired-like homeodomain transcription factor 2 (Pitx2) as a marker for cholinergic partition cells.
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| 6. |
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| 7. |
- Gage, PJ, et al.
(författare)
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Fate maps of neural crest and mesoderm in the mammalian eye
- 2005
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Ingår i: Investigative Ophthalmology & Visual Science. - : Association for Research in Vision and Ophthalmology (ARVO). - 1552-5783. ; 46:11, s. 4200-4208
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Tidskriftsartikel (refereegranskat)abstract
- PURPOSE. Structures derived from periocular mesenchyme arise by complex interactions between neural crest and mesoderm. Defects in development or function of structures derived from periocular mesenchyme result in debilitating vision loss, including glaucoma. The determination of long-term fates for neural crest and mesoderm in mammals has been inhibited by the lack of suitable marking systems. In the present study, the first long-term fate maps are presented for neural crest and mesoderm in a mammalian eye. METHODS. Complementary binary genetic approaches were used to mark indelibly the neural crest and mesoderm in the developing eye. Component one is a transgene expressing Cre recombinase under the control of an appropriate tissue-specific promoter. The second component is the conditional Cre reporter R26R, which is activated by the Cre recombinase expressed from the transgene. Lineage-marked cells were counterstained for expression of key transcription factors. RESULTS. The results established that fates of neural crest and mesoderm in mice were similar to but not identical with those in birds. They also showed that five early transcription factor genes are expressed in unique patterns in fate-marked neural crest and mesoderm during early ocular development. CONCLUSIONS. The data provide essential new information toward understanding the complex interactions required for normal development and function of the mammalian eye. The results also underscore the importance of confirming neural crest and mesoderm fates in a model mammalian system. The complementary systems used in this study should be useful for studying the respective cell fates in other organ systems.
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| 8. |
- Ganga, M, et al.
(författare)
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PITX2 isoform-specific regulation of atrial natriuretic factor expression - Synergism and repression with Nkx2.5
- 2003
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Ingår i: Journal of Biological Chemistry. - 1083-351X. ; 278:25, s. 22437-22445
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Tidskriftsartikel (refereegranskat)abstract
- PITX2 and Nkx2.5 are two of the earliest known transcriptional markers of vertebrate heart development. Pitx2(-/-) mice present with severe cardiac malformations and embryonic lethality, demonstrating a role for PITX2 in heart development. However, little is known about the downstream targets of PITX2 in cardiogenesis. We report here that the atrial natriuretic factor ( ANF) promoter is a target of PITX2. PITX2A, PITX2B, and PITX2C isoforms differentially activate the ANF promoter. However, only PITX2C can synergistically activate the ANF promoter in the presence of Nkx2.5. We further demonstrate that the procollagen lysyl hydroxylase ( PLOD1) promoter is regulated by Nkx2.5. Mechanistically, PITX2C and Nkx2.5 synergistically regulate ANF and PLOD1 expression through binding to their respective DNA elements. Surprisingly, PITX2A activation of the ANF and PLOD1 promoters is repressed by co- transfection of Nkx2.5 in the C3H10T1/ 2 embryonic fibroblast cell line. Pitx2a and Pitx2c are endogenously expressed in C3H10T1/ 2 cells, and these cells express factors that differentially regulate PITX2 isoform activities. We provide a new mechanism for the regulation of heart development by PITX2 isoforms through the regulation of ANF and PLOD1 gene expression and Nkx2.5 transcriptional activity.
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| 9. |
- Gu, Yuchen, et al.
(författare)
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Characterization of bone marrow laminins and identification of alpha5-containing laminins as adhesive proteins for multipotent hematopoietic FDCP-Mix cells
- 1999
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Ingår i: Blood. - 0006-4971. ; 93:8, s. 2533-2542
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Tidskriftsartikel (refereegranskat)abstract
- Laminins are extracellular matrix glycoproteins that influence the phenotype and functions of many types of cells. Laminins are heterotrimers composed of alpha, beta, and gamma polypeptides. So far five alpha, three beta, and two gamma polypeptide chains, and 11 variants of laminins have been proposed. Laminins interact in vitro with mature blood cells and malignant hematopoietic cells. Most studies have been performed with laminin-1 (alpha1beta1gamma1), and its expression in bone marrow is unclear. Employing an antiserum reacting with most laminin isoforms, we found laminins widely expressed in mouse bone marrow. However, no laminin alpha1 chain but rather laminin alpha2, alpha4, and alpha5 polypeptides were found in bone marrow. Our data suggest presence of laminin-2 (alpha2beta1gamma1), laminin-8 (alpha4beta1gamma1), and laminin-10 (alpha5beta1gamma1) in bone marrow. Northern blot analysis showed expression of laminin alpha1, alpha2, alpha4, and alpha5 chains in long-term bone marrow cultures, indicating upregulation of laminin alpha1 chain expression in vitro. Laminins containing alpha5 chain, in contrast to laminin-1, were strongly adhesive for multipotent hematopoietic FDCP-mix cells. Integrin alpha6 and beta1 chains mediated this adhesion, as shown by antibody perturbation experiments. Our findings indicate that laminins other than laminin-1 are functional in adhesive interactions in bone marrow.
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| 10. |
- Hjalt, Tord
(författare)
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Basic helix-loop-helix proteins expressed during early embryonic organogenesis.
- 2004
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Ingår i: International Review of Cytology. - 0074-7696. ; 236, s. 251-280
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Forskningsöversikt (refereegranskat)abstract
- The basic helix–loop–helix proteins form a special group of transcription factors unique for the eukaryotic organisms. They are crucial for the embryonic development of many fundamental organ systems such as muscle, heart, central nervous system, hematopoiteic system, and many others. They are very flexible in terms of regulating transcription in that they can either promote or repress transcription, and do so in many different ways. Basic helix–loop–helix proteins can form homo- or heterodimers with other members of the group, and are subject to post-transcriptional modifications. In this review, an overview of basic helix–loop–helix protein classification, biochemical function, and examples of past and recent advances in our understanding of embryonic development are presented, with emphasis on the vertebrate muscle, heart, brain, and eye.
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