Daniel
S. Kessler, Ph.D.
Assoc. Professor, Dept of Cell
and Developmental Biology
1110 BRB II/III
(215) 898-1478 FAX: (215) 573-7601
E-mail: kesslerd@mail.med.upenn.edu
Click here for selected publications since Dr. Kessler's arrival at Penn
RESEARCH INTERESTS
Vertebrate development; signal transduction; transcriptional regulation;
primary germ layers; Spemann's organizer.
RESEARCH TECHNIQUES
Molecular biological approaches include recombinant DNA, PCR, microarray
screening, protein expression, transcriptional analysis, and DNA-binding
assays. Embryological approaches include in vitro fertilization of amphibian
eggs, microinjection, microsurgery, in-situ hybridization, immunocytochemistry,
antisense and dominant negative inhibition of gene function, and transgenics.
RESEARCH SUMMARY
The emergence of the vertebrate body plan from the fertilized egg is a consequence
of numerous inductive, morphogenetic and differentiation events. In our
lab, we study the signal transduction and transcriptional mechanisms that
pattern the vertebrate embryo. The primary focus of our research with the
amphibian, Xenopus laevis, is the development of Spemann's organizer, a
specialized group of cells that regulates formation of the body plan, and
the development of the primary germ layers that form embryonic mesoderm
and endoderm. We are using biochemical, molecular and embryological approaches
to address two fundamental questions: 1) What are the signaling and transcriptional
regulatory pathways that establish and refine pattern in the gastrula; and
2) How is an individual signal used to generate distinct responses during
development? In our studies of organizer formation we have identified a
transcriptional cascade of activators and repressors that regulate organizer
formation and function. Ongoing studies in this area include the analysis
of Siamois, Twin and Goosecoid, homeobox genes required for organizer formation
and function. In our studies of germ layer formation, we have identified
signals required for mesodermal and endodermal development and have identified
genes that regulate the expression of and response to germ layer-inducing
signals. Ongoing studies address the role of VegT, a maternal T-box gene,
and Nodal-related members of the TGFbeta family, in mesodermal and endodermal
development. We are also studying FoxD3 and Sox17, transcription factors
that regulate the expression of Nodal genes and the cellular response to
Nodal proteins, respectively. The ultimate goal of our work is to identify
the critical genes and pathways that establish the major lineages and signaling
centers of the vertebrate embryo.
KEY WORDS:
Embryo; mesoderm; endoderm; organizer; induction; signaling; transcription
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