Abstract Detail

Development and Structure

Xu, Hengping [1], Jones, Daniel S. [1], Chesnut, Joshua [1], Anderson, Sarah [2], Johnson, Cameron [2], Khanday, Imtiyaz [2], Sundaresan, V. [2], Russell, Scott D. [1].

Control of Cell Cycle and Cellular Division in the Zygote of Oryza sativa.

Cell cycle control following sexual fusion of the egg and sperm cells involves an unusual interplay of the expressional contributions made by the two gametes and the emerging transcription of the zygote. This pattern of expression delineates the maternal to zygotic transition (MZT) and establishes the initial asymmetric division of the zygote that determines later cell fate. In the male and female gametes of Oryza sativa (rice), the cells that participate in forming the zygote are each at G1 at the time of gametic fusion. Therefore, the zygote undergoes expressional changes that potentially combine the maternal and paternal genome in assembling the complement of S-phase activated expression and subsequently triggering the genomic complement of the zygote to G2 at 9-12 hours after pollination (hap). A cyclin-dependent kinase (CDKA) occupies the central function of controlling the initiation of S-phase. Although the activation of CDKA is governed by changes in content of cyclin proteins, the advancement of the zygote into S-phase is inhibited by association with proteins called ICKs (inhibitors of cyclin-dependent kinases), which in plants are represented by Kip-Related Proteins (KRPs). In rice, these KRPs are likely targeted for removal and degradation by the association of F-box proteins that form skp1-cullin1-F-box protein (SCF) complexes, which are targeted for degradation in the proteosome, thus releasing the zygote from cell cycle inhibition. Recent analyses using yeast two-hybrid assays, cellular localizations and bimolecular fluorescence complementation of rice protoplasts provide evidence for the interaction of an F-box gene-encoded F-box/LRR motif protein with KRP5 and KRP4 in rice. This research is directed to verifying the origin and expression of regulatory subunits controlling S-phase in the rice zygote and determining whether their expression may be affected by transcript abundance in the male and female gametes and whether their later expression is under paternal or maternal control during the early asymmetric division of the zygote to determine cellular differences.

Related Links:
Sundaresan Lab
Russell Lab

1 - University of Oklahoma, Department of Microbiology and Plant Biology, Norman, OK, 73019
2 - University of California, Department of Plant Biology, Davis, CA, 95616

Keywords:
zygote
rice
cell cycle
embryo
Oryza sativa.

Presentation Type: Oral Paper
Session: 49, Developmental and Structure II
Location: 205/Savannah International Trade and Convention Center
Date: Wednesday, August 3rd, 2016
Time: 3:45 PM
Number: 49001
Abstract ID:793
Candidate for Awards:None