Dynamic changes of histone H3 trimethylated at positions K4 and K27 in human oocytes and preimplantation embryos

Capsule:
The levels of H3K4me3 and H3K27me3 show dynamic changes during human oocyte maturation and embryonic development. Asymmetric distribution of H3K27me3 exists in human zygote pronuclei, whereas H3K4me3 is always uniform.

Authors:
Aijun Zhang, Ph.D., Bufang Xu, Ph.D., Yijuan Sun, Ph.D., Xiaowei Lu, M.S., Ruihuan Gu, M.S., Ling Wu, M.S., Yun Feng, M.D., Ph.D., Chen Xu, M.D., Ph.D.

Volume 98, Issue 4, Pages 1009-1016, October 2012

Abstract:

Objective:
To investigate the distribution patterns of H3K4me3 and H3K27me3 in human oocytes and pre-implantation embryos.

Design:
Experimental study.

Setting:
University reproductive medical center.

Patient(s):
Patients undergoing in vitro fertilization (IVF) cycles.

Intervention(s):
Oocytes and embryos were collected from patients undergoing in vitro fertilization cycles.

Main Outcome Measure(s):
The distribution patterns of H3K4me3 and H3K27me3 in oocytes and embryos were analyzed by indirect immunofluorescent staining and scanning confocal microscopy.

Result(s):
H3K4me3 and H3K27me3 signals were detectable at each stage of oocyte and embryonic development. However, only one of the pronuclei showed signal for H3K27me3 in each of the zygotes, whereas H3K4me3 staining was always uniform in all zygotes. The level of H3K4me3 decreased steadily from GV to MII stage, obviously increased from zygote stage to 4-cell stage, and reached the lowest at 8-cell stage. A sharp increase was then observed at blastocyst stage. The level of H3K27me3 slightly changed from GV stage to zygote stage, then decreased steadily and reached the lowest at 8-cell stage, followed by a significant increase at blastocyst stage.

Conclusion(s):
The levels of H3K4me3 and H3K27me3 show dynamic changes during human oocyte maturation and pre-implantation embryonic development. Asymmetric distribution of H3K27me3 exists in human zygote pronuclei, whereas H3K4me3 is always uniform in all of the pronuclei.

  • Fernando Bronet

    Interesting study that point out the importance of the epigenetic in the embryonic development. Lately there are more and more articles studying changes and modifications in the metilation status and its importance in each particular step in the cleavage mechanism and we must study and learn more about this issue.

  • j.utah

    Great article identifying the presence and relative quantities of H3K4me3 and H3K27me3 during oocyte and embryo development. I look forward to future studies that identify where these and other histone modifications occur in the oocyte and embryo genome.

Translate »