Nucleolar dominance is a stable epigenetic phenomenon by which the rRNA genes of one parent are transcriptionally repressed in an F1 hybrid. Nucleolar dominance in hybrid cells is thought to be an extreme extension by which the non-hybrid cell may control the extant of ribosomal gene transcription. As an epigenetic process it is an attractive model for several reasons, most importantly it is completely reproducible, second, it is a general process that occurs through a broad range of plants and animals, finally, the processes that regulate transcription of rRNA genes are likely to play a transcriptional role genome wide. Dr. Pikaard's lab has extensive experience in investigating nucleolar dominance, additionally, in an NSF sponsored collaboration with a consortium of other labs, the Pikaard lab is now completing a two-year project in knocking out all of the known chromatin modifying genes in Arabidopsis. This greatly expands the tools by which I can begin studying this process.
My specific aims are to first identify genes that are involved in the process of establishing nucleolar dominance. I have started screening our collection of knockouts as well as creating novel mutants disrupted in their ability to induce nucleolar dominance. With these mutants in hand I will then be able to investigate the physical and genetic interactions between these genes. Finally, given the rapid advances in our analysis of chromatin structure, I will be able to examine how chromatin modification drives transcriptional silencing.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Postdoctoral Individual National Research Service Award (F32)
Project #
1F32GM069206-01
Application #
6692927
Study Section
Special Emphasis Panel (ZRG1-F05 (20))
Program Officer
Wolfe, Paul B
Project Start
2003-09-01
Project End
2006-08-31
Budget Start
2003-09-01
Budget End
2004-08-31
Support Year
1
Fiscal Year
2003
Total Cost
$39,700
Indirect Cost
Name
Washington University
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
068552207
City
Saint Louis
State
MO
Country
United States
Zip Code
63130
Preuss, Sasha; Pikaard, Craig S (2007) rRNA gene silencing and nucleolar dominance: insights into a chromosome-scale epigenetic on/off switch. Biochim Biophys Acta 1769:383-92
Caperta, Ana D; Neves, Nuno; Viegas, Wanda et al. (2007) Relationships between transcription, silver staining, and chromatin organization of nucleolar organizers in Secale cereale. Protoplasma 232:55-9
Pikaard, Craig S; Preuss, Sasha; Earley, Keith et al. (2005) Detecting differential expression of parental or progenitor alleles in genetic hybrids and allopolyploids. Methods Enzymol 395:554-69