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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
51

Molecular characterization of the CP2-related transcription factor, CRTR-1.

To, Sarah January 2009 (has links)
CRTR-1 is a member of the CP2 family of transcription factors. Unlike other CP2 family members, CRTR-1 expression is regulated developmentally. Major sites of expression in the embryo include the pluripotent inner cell mass (ICM) of the pre-implantation blastocyst and the developing kidney. It is also expressed in embryonic stem (ES) cells, which are derived from the ICM of blastocysts, and is downregulated as these cells differentiate into early primitive ectoderm-like (EPL) cells. This expression pattern suggests that CRTR-1 plays a role in early pluripotent populations. This thesis aims to characterize the transcription factor CRTR-1 at the molecular level and analyses the role of sumoylation on CRTR-1 function to develop a better understanding of the molecular role of CRTR-1 in ES cells. Luciferase reporter assays show that CRTR-1 is able to regulate the activities of other CP2 family members: CP2, NF2d9 and altNF2d9. It enhances CP2- and NF2d9-mediated activation but suppresses altNF2d9-mediated activation. To map the functional domains in the CRTR-1 protein, transactivation studies using CRTR-1 deletion mutants fused to the GAL4 DNA binding domain and a GAL4-responsive reporter system were performed. These studies map repressor activity to amino acids 48-200, but fail to identify a transactivation domain within the CRTR-1 protein. In order to understand the mechanisms by which CRTR-1 regulates the transcriptional activities of CP2 family members, a number of approaches are taken, including co-immunoprecipitation to show that CRTR-1 interacts with other CP2-like proteins, EMSA which demonstrate that CRTR-1 forms DNA binding complexes with CP2 family members, and subcellular protein localisation studies which reveal the ability of CRTR-1 and other family members to shuttle between the nucleus and cytoplasm via a CRM1-dependent pathway. In addition, the subcellular localisation of CRTR-1 appears to be cell type specific, with an exclusively nuclear localisation pattern in ES cells, a predominantly cytoplasmic localisation pattern in HEK293T cells, and a cytoplasmic and nuclear speckle localisation pattern in COS-1 cells. Co-expression of CRTR-1 with CP2 or NF2d9 results in the re-localisation of CRTR-1 to the cytoplasm in ES cells. The sumoylation enzymes Ubc9 and PIAS1 have previously been identified as CP2-interacting proteins (Kang et al., 2005a). Given the identification of two potential sumoylation sites within CRTR-1, FK³⁰ QE and LK⁴⁶ ⁴AE, and the ability for sumoylation to regulate transcription factor function, the possibility that CRTR-1 is regulated by sumoylation is investigated in this thesis. Immunoprecipitation experiments show that CRTR-1 is modified by SUMO-1 and that lysine 30 is the critical residue for this modification. Mutation of lysine 30 to alanine, which abolishes CRTR-1 sumoylation, results in enhancement of transactivation by CRTR-1, suggesting that sumoylation of CRTR-1 blocks maximal activation. Unexpectedly, however, overexpression of Ubc9, PIAS1, or SUMO-1 results in enhancement of CRTR-1 transcriptional activity, indicating that a more complex mechanism of regulation of CRTR-1 activity is likely. This thesis presents several novel properties of CRTR-1 and other CP2 family members, including the ability of CRTR-1, previously characterized as a repressor, to activate transcription. It is also the first demonstration that CP2 proteins are regulated by sumoylation and that they shuttle between the nucleus and cytoplasm via a CRM1-dependent mechanism. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1374290 / Thesis (Ph.D.) -- University of Adelaide, School of Molecular and Biomedical Science, 2009
52

Molecular characterization of the CP2-related transcription factor, CRTR-1.

To, Sarah January 2009 (has links)
CRTR-1 is a member of the CP2 family of transcription factors. Unlike other CP2 family members, CRTR-1 expression is regulated developmentally. Major sites of expression in the embryo include the pluripotent inner cell mass (ICM) of the pre-implantation blastocyst and the developing kidney. It is also expressed in embryonic stem (ES) cells, which are derived from the ICM of blastocysts, and is downregulated as these cells differentiate into early primitive ectoderm-like (EPL) cells. This expression pattern suggests that CRTR-1 plays a role in early pluripotent populations. This thesis aims to characterize the transcription factor CRTR-1 at the molecular level and analyses the role of sumoylation on CRTR-1 function to develop a better understanding of the molecular role of CRTR-1 in ES cells. Luciferase reporter assays show that CRTR-1 is able to regulate the activities of other CP2 family members: CP2, NF2d9 and altNF2d9. It enhances CP2- and NF2d9-mediated activation but suppresses altNF2d9-mediated activation. To map the functional domains in the CRTR-1 protein, transactivation studies using CRTR-1 deletion mutants fused to the GAL4 DNA binding domain and a GAL4-responsive reporter system were performed. These studies map repressor activity to amino acids 48-200, but fail to identify a transactivation domain within the CRTR-1 protein. In order to understand the mechanisms by which CRTR-1 regulates the transcriptional activities of CP2 family members, a number of approaches are taken, including co-immunoprecipitation to show that CRTR-1 interacts with other CP2-like proteins, EMSA which demonstrate that CRTR-1 forms DNA binding complexes with CP2 family members, and subcellular protein localisation studies which reveal the ability of CRTR-1 and other family members to shuttle between the nucleus and cytoplasm via a CRM1-dependent pathway. In addition, the subcellular localisation of CRTR-1 appears to be cell type specific, with an exclusively nuclear localisation pattern in ES cells, a predominantly cytoplasmic localisation pattern in HEK293T cells, and a cytoplasmic and nuclear speckle localisation pattern in COS-1 cells. Co-expression of CRTR-1 with CP2 or NF2d9 results in the re-localisation of CRTR-1 to the cytoplasm in ES cells. The sumoylation enzymes Ubc9 and PIAS1 have previously been identified as CP2-interacting proteins (Kang et al., 2005a). Given the identification of two potential sumoylation sites within CRTR-1, FK³⁰ QE and LK⁴⁶ ⁴AE, and the ability for sumoylation to regulate transcription factor function, the possibility that CRTR-1 is regulated by sumoylation is investigated in this thesis. Immunoprecipitation experiments show that CRTR-1 is modified by SUMO-1 and that lysine 30 is the critical residue for this modification. Mutation of lysine 30 to alanine, which abolishes CRTR-1 sumoylation, results in enhancement of transactivation by CRTR-1, suggesting that sumoylation of CRTR-1 blocks maximal activation. Unexpectedly, however, overexpression of Ubc9, PIAS1, or SUMO-1 results in enhancement of CRTR-1 transcriptional activity, indicating that a more complex mechanism of regulation of CRTR-1 activity is likely. This thesis presents several novel properties of CRTR-1 and other CP2 family members, including the ability of CRTR-1, previously characterized as a repressor, to activate transcription. It is also the first demonstration that CP2 proteins are regulated by sumoylation and that they shuttle between the nucleus and cytoplasm via a CRM1-dependent mechanism. / http://proxy.library.adelaide.edu.au/login?url= http://library.adelaide.edu.au/cgi-bin/Pwebrecon.cgi?BBID=1374290 / Thesis (Ph.D.) -- University of Adelaide, School of Molecular and Biomedical Science, 2009
53

Endocardial cells are a distinct endothelial lineage derived from multipotent cardiovascular progenitors

Misfeldt, Andrew Michael. January 2008 (has links)
Thesis (Ph. D. in Cell and Developmental Biology)--Vanderbilt University, Dec. 2008. / Title from title screen. Includes bibliographical references.
54

Three dimensional culture and in vitro chondrogenic differentiation of mouse embryonic stem cell in collagen microsphere

Yeung, Chiu-wai. January 2009 (has links)
Thesis (Ph. D.)--University of Hong Kong, 2009. / Includes bibliographical references (leaves 162-215). Also available in print.
55

Tuneable collagen scaffolds for the directed differentiation of embryonic stem cells toward neural lineages

Monteiro, Gary Albert, January 2010 (has links)
Thesis (Ph. D.)--Rutgers University, 2010. / "Graduate Program in Biomedical Engineering." Includes bibliographical references.
56

A comparative study on the effects of feeder cells on culture of human embryonic stem cells /

Hou, Yuen-chi, Denise. January 2009 (has links)
Thesis (M. Phil.)--University of Hong Kong, 2010. / Includes bibliographical references (leaves 136-153). Also available online.
57

Over-expression of epidermal growth factor precursor in vitro and in vivo /

Kwan, Wing-po, Rainbow. January 1998 (has links)
Thesis (M. Phil.)--University of Hong Kong, 1998. / Includes bibliographical references (leaves 151-168).
58

Derivation, characterization and differentiation of feeder-free human embryonic stem cells /

Bigdeli, Narmin, January 2010 (has links)
Diss. (sammanfattning) Göteborg : Göteborgs universitet, 2010. / Härtill 4 uppsatser.
59

Modelling endocrine pancreas development in mouse embryonic stem cells by activation of Pdx1 gene

Bernardo, Andreia. January 2008 (has links)
Thesis (Ph.D.)--Aberdeen University, 2008. / Title from web page (viewed on July 14, 2009). Includes bibliographical references.
60

Embryonic stem cell culture in fibrous bed bioreactor

Ouyang, Anli, January 2006 (has links)
Thesis (Ph. D.)--Ohio State University, 2006. / Title from first page of PDF file. Includes bibliographical references (p. 211-229).

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