The mouse oocyte is a non-proliferating, differentiated cell. Following fertilization and the first round of DNA replication, the 2-cell stage blastomeres, which contain the first zygotic nuclei, are totipotent. This remarkable transformation probably entails reprogramming the pattern of gene expression. The molecular basis for this reprogramming is poorly understood.
Specific Aim 1 will (1) examine the role of DNA replication in this reprogramming and will identify genes by mRNA differential display whose expression is coupled to the first round of DNA replication, (2) determine if a competition between maternally- derived histones and transcription factors controls the timing for the onset of zygotic transcription and the spectrum of genes that are expressed by expanding the endogenous histone pool via microinjection and then assaying for the expression of specific markers of zygotic gene activation and (3) assess the role of chromatin structure in the reprogramming of gene expression. Following genome activation, the blastomeres are totipotent up to the 8-cell stage. A spatial reprogramming in the pattern of gene expression in the morula correlates with cell specification and differentiation of the outer cells into trophectoderm and the maintenance of totipotency of the inner cell mass cells that give rise to the embryo proper. The molecular basis that underlies this spatial change in the pattern of gene expression is also poorly understood.
Specific Aim 2 will use an RT-PCR based method coupled with mRNA differential display to identify genes whose expression is spatially restricted in the blastocyst. These genes, and genes whose spatial pattern of expression is already known to be restricted in the blastocyst, will then be used as markers to determine when these changes in expression are first detected and the role of cell-cell contract in their spatial expression patterns. Last, changes in TAT-box and enhancer utilization will be examined using a series of reporter transgenes driven by different combinations of TATA-box and enhancer elements to determine if changes in promoter utilization may contribute to the spatial differences in gene expression. By providing new information regarding gene expression in the preimplantation embryo, these studies will expand our basic understanding of how the preimplantation embryo executes its essential functions of cell proliferation and differentiation; failure to execute successfully this program may contribute to the high degree of embryo loss that occurs prior to implantation.

Agency
National Institute of Health (NIH)
Institute
Eunice Kennedy Shriver National Institute of Child Health & Human Development (NICHD)
Type
Method to Extend Research in Time (MERIT) Award (R37)
Project #
5R37HD022681-14
Application #
6182027
Study Section
Reproductive Biology Study Section (REB)
Program Officer
Tasca, Richard J
Project Start
1987-09-01
Project End
2002-08-31
Budget Start
2000-09-01
Budget End
2001-08-31
Support Year
14
Fiscal Year
2000
Total Cost
$266,032
Indirect Cost
Name
University of Pennsylvania
Department
Biology
Type
Schools of Arts and Sciences
DUNS #
042250712
City
Philadelphia
State
PA
Country
United States
Zip Code
19104
Abe, Ken-Ichiro; Funaya, Satoshi; Tsukioka, Dai et al. (2018) Minor zygotic gene activation is essential for mouse preimplantation development. Proc Natl Acad Sci U S A 115:E6780-E6788
Horvat, Filip; Fulka, Helena; Jankele, Radek et al. (2018) Role of Cnot6l in maternal mRNA turnover. Life Sci Alliance 1:e201800084
Franke, Vedran; Ganesh, Sravya; Karlic, Rosa et al. (2017) Long terminal repeats power evolution of genes and gene expression programs in mammalian oocytes and zygotes. Genome Res 27:1384-1394
Mayer, Alexandra; Baran, Vladimir; Sakakibara, Yogo et al. (2016) DNA damage response during mouse oocyte maturation. Cell Cycle 15:546-58
Ma, P; Schultz, R M (2016) HDAC1 and HDAC2 in mouse oocytes and preimplantation embryos: Specificity versus compensation. Cell Death Differ 23:1119-27
Svoboda, Petr; Franke, Vedran; Schultz, Richard M (2015) Sculpting the Transcriptome During the Oocyte-to-Embryo Transition in Mouse. Curr Top Dev Biol 113:305-49
Balboula, Ahmed Z; Stein, Paula; Schultz, Richard M et al. (2015) RBBP4 regulates histone deacetylation and bipolar spindle assembly during oocyte maturation in the mouse. Biol Reprod 92:105
Jimenez, Richard; Melo, Eduardo O; Davydenko, Olga et al. (2015) Maternal SIN3A regulates reprogramming of gene expression during mouse preimplantation development. Biol Reprod 93:89
Abe, Ken-Ichiro; Yamamoto, Ryoma; Franke, Vedran et al. (2015) The first murine zygotic transcription is promiscuous and uncoupled from splicing and 3' processing. EMBO J 34:1523-37
Stein, Paula; Rozhkov, Nikolay V; Li, Fan et al. (2015) Essential Role for endogenous siRNAs during meiosis in mouse oocytes. PLoS Genet 11:e1005013

Showing the most recent 10 out of 141 publications