Establishment of polarity in the egg can be described as the earliest step in embryonic patterning. A single cell, the fertilized egg, contains the information that will ultimately specify the entire organism. As the egg divides during the early stages of development, different cells acquire different fates. One mechanism to account for this difference in developmental potential is the sequestering of molecules in the egg that could specify such potential. It is a long-standing proposal that localization of maternal factors in eggs can provide the basis for pattern in the early embryo, and while there is evidence for the existence of localized cytoplasmic determinants in many systems, in no case is the localization process understood. This research proposal addresses this problem by investigating the localization of specific maternal mRNAs in the frog egg.
The aim of the proposed research is to understand the means by which RNA is localized to specified regions within a cell. The Xenopus oocyte provides an excellent model system in which to study this problem. Chief among the experimental advantages in this system are a rapid injection assay for localization, and ease in obtaining large amounts of material for biochemical studies. Three lines of investigation are proposed to study RNA localization: (1) Experiments are proposed to identify and isolate components of the localization apparatus. The biochemistry of RNA localization is not currently understood. By addressing this issue, new information should be gained concerning the molecular apparatus involved in moving macromolecules to defined regions of the oocyte cytoplasm. (2) To address certain mechanistic questions, experiments are proposed to probe the role of the cytoskeleton in RNA localization. (3) In order to allow understanding of how particular RNAs are recognized as requiring localization, experiments are proposed to characterize the RNA signal for localization. These experiments may provide insights not only into how developmental signals are localized, but also the role this may play in cell type determination. Currently, it is not understood how developmental signals are localized to determine cell type during early development. The experiments proposed here address that problem, and may contribute towards understanding how developmental programs are disrupted in certain diseases. To understand the means by which cellular processes can go awry, it will first be necessary to gain a basic understanding of normal development and differentiation.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Research Project (R01)
Project #
5R01HD030699-04
Application #
2203032
Study Section
Cellular Biology and Physiology Subcommittee 1 (CBY)
Project Start
1993-09-01
Project End
1999-08-31
Budget Start
1996-09-01
Budget End
1999-08-31
Support Year
4
Fiscal Year
1996
Total Cost
Indirect Cost
Name
Brown University
Department
Biochemistry
Type
Schools of Medicine
DUNS #
001785542
City
Providence
State
RI
Country
United States
Zip Code
02912
King, Mary Lou; Messitt, Timothy J; Mowry, Kimberly L (2005) Putting RNAs in the right place at the right time: RNA localization in the frog oocyte. Biol Cell 97:19-33
Lewis, Raymond A; Kress, Tracy L; Cote, Colette A et al. (2004) Conserved and clustered RNA recognition sequences are a critical feature of signals directing RNA localization in Xenopus oocytes. Mech Dev 121:101-9
Chang, Patrick; Torres, Jan; Lewis, Raymond A et al. (2004) Localization of RNAs to the mitochondrial cloud in Xenopus oocytes through entrapment and association with endoplasmic reticulum. Mol Biol Cell 15:4669-81
Yoon, Young J; Mowry, Kimberly L (2004) Xenopus Staufen is a component of a ribonucleoprotein complex containing Vg1 RNA and kinesin. Development 131:3035-45
Kress, Tracy L; Yoon, Young J; Mowry, Kimberly L (2004) Nuclear RNP complex assembly initiates cytoplasmic RNA localization. J Cell Biol 165:203-11
Xie, Jiuyong; Lee, Ji-Ann; Kress, Tracy L et al. (2003) Protein kinase A phosphorylation modulates transport of the polypyrimidine tract-binding protein. Proc Natl Acad Sci U S A 100:8776-81
Bubunenko, Mikhail; Kress, Tracy L; Vempati, Uma Devi et al. (2002) A consensus RNA signal that directs germ layer determinants to the vegetal cortex of Xenopus oocytes. Dev Biol 248:82-92
Cote, C A; Gautreau, D; Denegre, J M et al. (1999) A Xenopus protein related to hnRNP I has a role in cytoplasmic RNA localization. Mol Cell 4:431-7
Mowry, K L; Cote, C A (1999) RNA sorting in Xenopus oocytes and embryos. FASEB J 13:435-45
Gautreau, D; Cote, C A; Mowry, K L (1997) Two copies of a subelement from the Vg1 RNA localization sequence are sufficient to direct vegetal localization in Xenopus oocytes. Development 124:5013-20

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