Two kinds of 5S RNA multigene families exist in the genome of Xenopus. The oocyte-type 5S RNA genes function only in the oocyte and are repressed in somatic cells. The somatic 5S RNA genes are transcribed actively in both cocytes and somatic cells. The expression of these genes can be assayed by the synthesis of 5S RNA in vitro, in vivo, or with isolated chromatin. The goal of these experiments is to reproduce in vitro with purified components the same differential control of gene activity that is seen in vivo. In somatic cells of Xenopus, active 5S RNA genes are associated with transcription factors to form stable transcription complexes. Repressed genes are not associated with these factors but rather complexed with nucleosomes that keep transcription factors from forming complexes with the gene. Both the active and repressed state of 5S RNA genes are stable. One purpose of this project is to identify the molecules associated with active and repressed complexes and characterize the details of how they interact with each other and with DNA signals in and around the 5S RNA gene. The gene for the 5S-specific positive transcription factor (TFIIIA) will be cloned, expressed in E. coli, and mutants prepared in order to map further the functional amino acids of the protein that bind to critical regions of the internal control region of the 5S RNA gene and to other components of the transcription complex. A transient developmental expression assay is sought that will reproduce the control of the two kinds of 5S RNA genes that occurs during early embryogenesis. From this assay, the exact DNA sequences in the 5S RNA gene involved in the developmental control, as well as the molecules in embryos that are responsible for reading the DNA signals, will be elucidated. In addition, this assay will be designed to determine how discrimination between two genes is established and then perpetuated in early embryogenesis. It is suggested that these stable transcription complexes might play a role in the phenomenon of determination or """"""""commitment"""""""" of genes in development. Some experimental schemes will test this proposal.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Project (R01)
Project #
5R01GM022395-13
Application #
3271129
Study Section
Molecular Biology Study Section (MBY)
Project Start
1975-09-01
Project End
1990-08-31
Budget Start
1987-09-01
Budget End
1988-08-31
Support Year
13
Fiscal Year
1987
Total Cost
Indirect Cost
Name
Carnegie Institution of Washington, D.C.
Department
Type
DUNS #
072641707
City
Washington
State
DC
Country
United States
Zip Code
20005
Mukhi, Sandeep; Brown, Donald D (2011) Transdifferentiation of tadpole pancreatic acinar cells to duct cells mediated by Notch and stromelysin-3. Dev Biol 351:311-7
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Cai, Liquan; Das, Biswajit; Brown, Donald D (2007) Changing a limb muscle growth program into a resorption program. Dev Biol 304:260-71
Furlow, J D; Brown, D D (1999) In vitro and in vivo analysis of the regulation of a transcription factor gene by thyroid hormone during Xenopus laevis metamorphosis. Mol Endocrinol 13:2076-89
Wolffe, A P; Brown, D D (1988) Developmental regulation of two 5S ribosomal RNA genes. Science 241:1626-32
Setzer, D R; Brown, D D (1985) Formation and stability of the 5 S RNA transcription complex. J Biol Chem 260:2483-92
Brown, D D; Schlissel, M S (1985) The molecular basis of differential gene expression of two 5S RNA genes. Cold Spring Harb Symp Quant Biol 50:549-53