51
|
|
52
|
Parry JM, Velarde NV, Lefkovith AJ, Zegarek MH, Hang JS, Ohm J, Klancer R, Maruyama R, Druzhinina MK, Grant BD, Piano F, Singson A. EGG-4 and EGG-5 Link Events of the Oocyte-to-Embryo Transition with Meiotic Progression in C. elegans. Curr Biol 2010; 19:1752-7. [PMID: 19879147 DOI: 10.1016/j.cub.2009.09.015] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2008] [Revised: 08/31/2009] [Accepted: 09/01/2009] [Indexed: 11/19/2022]
Abstract
The molecular underpinnings of the oocyte-to-embryo transition are poorly understood. Here we show that two protein tyrosine phosphatase-like (PTPL) family proteins, EGG-4 and EGG-5, are required for key events of the oocyte-to-embryo transition in Caenorhabditis elegans. The predicted EGG-4 and EGG-5 amino acid sequences are 99% identical and their functions are redundant. In embryos lacking EGG-4 and EGG-5, we observe defects in meiosis, polar body formation, the block to polyspermy, F-actin dynamics, and eggshell deposition. During oogenesis, EGG-4 and EGG-5 assemble at the oocyte cortex with the previously identified regulators or effectors of the oocyte-to-embryo transition EGG-3, CHS-1, and MBK-2 [1, 2]. All of these molecules share a complex interdependence with regards to their dynamics and subcellular localization. Shortly after fertilization, EGG-4 and EGG-5 are required to properly coordinate a redistribution of CHS-1 and EGG-3 away from the cortex during meiotic anaphase I. Therefore, EGG-4 and EGG-5 are not only required for critical events of the oocyte-to-embryo transition but also link the dynamics of the regulatory machinery with the advancing cell cycle.
Collapse
Affiliation(s)
- Jean M Parry
- Waksman Institute and Department of Genetics, Rutgers University, Piscataway, NJ 08854, USA
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
53
|
McNally KL, Martin JL, Ellefson M, McNally FJ. Kinesin-dependent transport results in polarized migration of the nucleus in oocytes and inward movement of yolk granules in meiotic embryos. Dev Biol 2009; 339:126-40. [PMID: 20036653 DOI: 10.1016/j.ydbio.2009.12.021] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2009] [Revised: 12/11/2009] [Accepted: 12/16/2009] [Indexed: 01/28/2023]
Abstract
During female meiosis, meiotic spindles are positioned at the oocyte cortex to allow expulsion of chromosomes into polar bodies. In C. elegans, kinesin-dependent translocation of the entire spindle to the cortex precedes dynein-dependent rotation of one spindle pole toward the cortex. To elucidate the role of kinesin-1 in spindle translocation, we examined the localization of kinesin subunits in meiotic embryos. Surprisingly, kinesin-1 was not associated with the spindle and instead was restricted to the cytoplasm in the middle of the embryo. Yolk granules moved on linear tracks, in a kinesin-dependent manner, away from the cortex, resulting in their concentration in the middle of the embryo where the kinesin was concentrated. These results suggest that cytoplasmic microtubules might be arranged with plus ends extending inward, away from the cortex. This microtubule arrangement would not be consistent with direct transport of the meiotic spindle toward the cortex by kinesin-1. In maturing oocytes, the nucleus underwent kinesin-dependent migration to the future site of spindle attachment at the anterior cortex. Thus the spindle translocation defect observed in kinesin-1 mutants may be a result of failed nuclear migration, which places the spindle too far from the cortex for the spindle translocation mechanism to function.
Collapse
Affiliation(s)
- Karen L McNally
- Section of Molecular and Cellular Biology, 149 Briggs Hall, University of California, Davis, Davis, CA 95616, USA
| | | | | | | |
Collapse
|
54
|
Cheng KCC, Klancer R, Singson A, Seydoux G. Regulation of MBK-2/DYRK by CDK-1 and the pseudophosphatases EGG-4 and EGG-5 during the oocyte-to-embryo transition. Cell 2009; 139:560-72. [PMID: 19879842 DOI: 10.1016/j.cell.2009.08.047] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2008] [Revised: 06/04/2009] [Accepted: 08/26/2009] [Indexed: 02/04/2023]
Abstract
DYRKs are kinases that self-activate in vitro by autophosphorylation of a YTY motif in the kinase domain, but their regulation in vivo is not well understood. In C. elegans zygotes, MBK-2/DYRK phosphorylates oocyte proteins at the end of the meiotic divisions to promote the oocyte-to-embryo transition. Here we demonstrate that MBK-2 is under both positive and negative regulation during the transition. MBK-2 is activated during oocyte maturation by CDK-1-dependent phosphorylation of serine 68, a residue outside of the kinase domain required for full activity in vivo. The pseudotyrosine phosphatases EGG-4 and EGG-5 sequester activated MBK-2 until the meiotic divisions by binding to the YTY motif and inhibiting MBK-2's kinase activity directly, using a mixed-inhibition mechanism that does not involve tyrosine dephosphorylation. Our findings link cell-cycle progression to MBK-2/DYRK activation and the oocyte-to-embryo transition.
Collapse
Affiliation(s)
- Ken Chih-Chien Cheng
- Department of Molecular Biology and Genetics and Howard Hughes Medical Institute, Center for Cell Dynamics, Johns Hopkins School of Medicine, 725 N. Wolfe Street, PCTB 706, Baltimore, MD 21205, USA
| | | | | | | |
Collapse
|
55
|
Heighington CS, Kipreos ET. Embryogenesis: Degenerate phosphatases control the oocyte-to-embryo transition. Curr Biol 2009; 19:R939-41. [PMID: 19889367 DOI: 10.1016/j.cub.2009.09.032] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The oocyte-to-embryo transition requires drastic reorganizations within a short timeframe. Recent studies show that, in the nematode Caenorhabditis elegans, phosphotyrosine-binding pseudo-phosphatases are key regulators of this critical developmental transition.
Collapse
|
56
|
Johnson JLFA, Lu C, Raharjo E, McNally K, McNally FJ, Mains PE. Levels of the ubiquitin ligase substrate adaptor MEL-26 are inversely correlated with MEI-1/katanin microtubule-severing activity during both meiosis and mitosis. Dev Biol 2009; 330:349-57. [PMID: 19361490 DOI: 10.1016/j.ydbio.2009.04.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2008] [Revised: 03/04/2009] [Accepted: 04/02/2009] [Indexed: 10/20/2022]
Abstract
The MEI-1/MEI-2 microtubule-severing complex, katanin, is required for oocyte meiotic spindle formation and function in C. elegans, but the microtubule-severing activity must be quickly downregulated so that it does not interfere with formation of the first mitotic spindle. Post-meiotic MEI-1 inactivation is accomplished by two parallel protein degradation pathways, one of which requires MEL-26, the substrate-specific adaptor that recruits MEI-1 to a CUL-3 based ubiquitin ligase. Here we address the question of how MEL-26 mediated MEI-1 degradation is triggered only after the completion of MEI-1's meiotic function. We find that MEL-26 is present only at low levels until the completion of meiosis, after which protein levels increase substantially, likely increasing the post-meiotic degradation of MEI-1. During meiosis, MEL-26 levels are kept low by the action of another type of ubiquitin ligase, which contains CUL-2. However, we find that the low levels of meiotic MEL-26 have a subtle function, acting to moderate MEI-1 activity during meiosis. We also show that MEI-1 is the only essential target for MEL-26, and possibly for the E3 ubiquitin ligase CUL-3, but the upstream ubiquitin ligase activating enzyme RFL-1 has additional essential targets.
Collapse
Affiliation(s)
- Jacque-Lynne F A Johnson
- Genes and Development Research Group, Department of Biochemistry and Molecular Biology, University of Calgary, Calgary, AB, Canada T2N 4N1
| | | | | | | | | | | |
Collapse
|
57
|
Chi W, Reinke V. DPL-1 (DP) acts in the germ line to coordinate ovulation and fertilization in C. elegans. Mech Dev 2009; 126:406-16. [PMID: 19368797 DOI: 10.1016/j.mod.2009.01.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2008] [Revised: 01/27/2009] [Accepted: 01/27/2009] [Indexed: 11/26/2022]
Abstract
Proper coordination of oogenesis, ovulation, and fertilization is essential for successful reproduction. In Caenorhabditis elegans, a strong loss-of-function mutation in dpl-1, which encodes a subunit of the E2F heterodimeric transcription factor EFL-1/DPL-1, causes severe defects during ovulation and fertilization. Here we demonstrate that the somatic gonad structure and sheath cell contraction rate appear normal in dpl-1 mutants, but that dilation of the spermatheca valve does not occur properly, causing oocytes to become trapped in the proximal gonad arm and enter endomitosis. This ovulation defect can be partially suppressed by increasing the activity of ITR-1, an inositol triphosphate receptor in the spermatheca that promotes dilation in response to IP(3) signaling. Tissue-specific rescue experiments demonstrate that expression of DPL-1 in germ cells but not the spermatheca can restore both ovulation and fertilization in dpl-1 mutants, indicating that the absence of DPL-1 likely disrupts a pro-ovulation signal originating in the oocyte that in turn stimulates the spermatheca. Moreover, we found that expression of a single EFL-1/DPL-1-responsive gene, rme-2, in the germ line of dpl-1 mutants significantly rescues ovulation, but not fertilization. Instead, other EFL-1/DPL-1-responsive genes function to promote successful fertilization. We propose that DPL-1 acts with EFL-1 in developing oocytes to directly regulate a transcriptional program that couples the critical events of ovulation and fertilization.
Collapse
Affiliation(s)
- Woo Chi
- Department of Genetics, Yale University School of Medicine, New Haven, CT 06510, USA
| | | |
Collapse
|
58
|
Sato M, Grant BD, Harada A, Sato K. Rab11 is required for synchronous secretion of chondroitin proteoglycans after fertilization in Caenorhabditis elegans. J Cell Sci 2008; 121:3177-86. [PMID: 18765566 DOI: 10.1242/jcs.034678] [Citation(s) in RCA: 75] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
We previously identified a novel type of caveolin-enriched secretory vesicle in Caenorhabditis elegans oocytes. These vesicles undergo synchronous fusion with the plasma membrane immediately after fertilization, suggesting that they could be cortical granules that have been described in diverse animal species. Here, we report that these vesicles are indeed cortical granules, delivering essential chondroitin proteoglycans and mucin-like glycoproteins to the early embryonic extracellular matrices (ECMs). Furthermore, we have found that the small GTPase RAB-11 and the target-SNARE SYN-4 are required for cortical granule excoytosis after fertilization. In oocytes, SYN-4 localizes mainly to the plasma membrane, whereas GFP::RAB-11 accumulates transiently on the cortical granules during ovulation, immediately prior to fertilization. Importantly, cytokinesis defects in early embryos are commonly observed after depletion of either rab-11 or syn-4, producing a phenotype very similar to that observed after blockade of chondroitin synthesis. Taken together, our results indicate that at least part of the essential role for RAB-11 and SYN-4 in early embryogenesis is in the targeting of cortical granules to the plasma membrane during the precisely regulated secretion of ECM components.
Collapse
Affiliation(s)
- Miyuki Sato
- Laboratory of Molecular Traffic, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi, Gunma, Japan
| | | | | | | |
Collapse
|
59
|
Cheng H, Govindan JA, Greenstein D. Regulated trafficking of the MSP/Eph receptor during oocyte meiotic maturation in C. elegans. Curr Biol 2008; 18:705-714. [PMID: 18472420 DOI: 10.1016/j.cub.2008.04.043] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2008] [Revised: 04/18/2008] [Accepted: 04/21/2008] [Indexed: 01/15/2023]
Abstract
BACKGROUND In C. elegans, a sperm-sensing mechanism regulates oocyte meiotic maturation and ovulation, tightly coordinating sperm availability and embryo production; sperm release the major sperm protein (MSP) signal to trigger meiotic resumption. Meiotic arrest depends on the parallel function of the oocyte VAB-1 MSP/Eph receptor and somatic G protein signaling. MSP promotes meiotic maturation by antagonizing Eph receptor signaling and counteracting inhibitory inputs from the gonadal sheath cells. RESULTS Here, we present evidence suggesting that in the absence of the MSP ligand, the VAB-1 Eph receptor inhibits meiotic maturation while either in or in transit to the endocytic-recycling compartment. VAB-1::GFP localization to the RAB-11-positive endocytic-recycling compartment is independent of ephrins but is antagonized by MSP signaling. Two negative regulators of oocyte meiotic maturation, DAB-1/Disabled and RAN-1, interact with the VAB-1 receptor and are required for its accumulation in the endocytic-recycling compartment in the absence of MSP or sperm (hereafter referred to as MSP/sperm). Inactivation of the endosomal recycling regulators rme-1 or rab-11.1 causes a vab-1-dependent reduction in the meiotic-maturation rate in the presence of MSP/sperm. Further, we show that Galpha(s) signaling in the gonadal sheath cells, which is required for meiotic maturation in the presence of MSP/sperm, affects VAB-1::GFP trafficking in oocytes. CONCLUSIONS Regulated endocytic trafficking of the VAB-1 MSP/Eph receptor contributes to the control of oocyte meiotic maturation in C. elegans. Eph receptor trafficking in other systems may be influenced by the conserved proteins DAB-1/Disabled and RAN-1 and by crosstalk with G protein signaling in neighboring cells.
Collapse
Affiliation(s)
- Hua Cheng
- Department of Genetics, Cell Biology and Development, University of Minnesota, 6-160 Jackson Hall, 321 Church Street SE, Minneapolis, Minnesota 55455; Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
| | - J Amaranath Govindan
- Department of Genetics, Cell Biology and Development, University of Minnesota, 6-160 Jackson Hall, 321 Church Street SE, Minneapolis, Minnesota 55455; Department of Cell and Developmental Biology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232
| | - David Greenstein
- Department of Genetics, Cell Biology and Development, University of Minnesota, 6-160 Jackson Hall, 321 Church Street SE, Minneapolis, Minnesota 55455.
| |
Collapse
|
60
|
Horner VL, Wolfner MF. Transitioning from egg to embryo: Triggers and mechanisms of egg activation. Dev Dyn 2008; 237:527-44. [DOI: 10.1002/dvdy.21454] [Citation(s) in RCA: 150] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
|
61
|
|
62
|
Stitzel ML, Cheng KCC, Seydoux G. Regulation of MBK-2/Dyrk Kinase by Dynamic Cortical Anchoring during the Oocyte-to-Zygote Transition. Curr Biol 2007; 17:1545-54. [PMID: 17869113 DOI: 10.1016/j.cub.2007.08.049] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2007] [Revised: 08/02/2007] [Accepted: 08/03/2007] [Indexed: 11/15/2022]
Abstract
BACKGROUND Successful transition from oocyte to zygote depends on the timely degradation of oocyte proteins to prepare for embryonic development. In C. elegans, degradation of the oocyte protein MEI-1 depends on MBK-2, a kinase that phosphorylates MEI-1 shortly after fertilization during the second meiotic division. RESULTS Here we report that precise timing of MEI-1 phosphorylation depends on the cell cycle-regulated release of MBK-2 from the cortex. Prior to the meiotic divisions, MBK-2 is tethered at the cortex by EGG-3, an oocyte protein required for egg activation (see [1], accompanying paper in this issue). During the meiotic divisions, EGG-3 is internalized and degraded in an APC/C (anaphase-promoting complex/cyclosome)-dependent manner. EGG-3 internalization and degradation correlate with MBK-2 release from the cortex and MEI-1 phosphorylation in the cytoplasm. In an egg-3 mutant, MEI-1 is phosphorylated and degraded prematurely. CONCLUSION We suggest that successful transition from an oocyte to a zygote depends on the cell cycle-regulated relocalization of key regulators from the cortex to the cytoplasm of the egg.
Collapse
Affiliation(s)
- Michael L Stitzel
- Department of Molecular Biology and Genetics, Howard Hughes Medical Institute, Center for Cell Dynamics, Johns Hopkins School of Medicine, 725 North Wolfe Street, PCTB 706, Baltimore, Maryland 21205, USA
| | | | | |
Collapse
|