Revealing transcriptome and methylome landscapes in a human oocyte by parallel sequencing
Invited conference paper presented and published in conference proceedings


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AbstractOocyte quality plays a critical role in fertility, embryonic development and fetal health. Previous studies have reported that morphological assessment is limited and was not associated with fertilization rate, embryo quality or implantation rate after intracytoplasmic sperm injection. Molecular assessment based on genetics and epigenetics signatures would be an alternative strategy. With the recent development of single cell sequencing technologies, several studies have established single oocyte transcriptome and methylome profiles separately.
In this study, we aimed to profile the simultaneous transcriptome and methylome landscapes in a single human oocytes by adopting a modified single cell parallel methylome and transcriptome sequencing (scM&T-seq). We performed scM&T-seq on two oocytes donated from a 32-year-old in vitro fertilization patient through follicle induction approach. A total of 10317 genes were commonly expressed in the two oocytes, and the correlation of two transcriptomes was 0.984 using Pearson’s correlation test. For RRBS libraries, the mapping efficiency was 25.1% and 26.9% respectively, whereas the bisulfite conversion ratios were 98.5% and 96.7% respectively. We detected 222,335-464,057 CpG sites covered by at least one reads and 146,040-322,323 CpG sites covered by at least five reads. Two samples shared 3450 CpG islands. Nearly half of detected CpG sites (43% and 45%) were located in gene promoters and the majority of CpG sites were annotated in CpG islands or shores. A high correlation (R=0.870) of methylation level between two single oocytes was observed in 1000-bp bin size window. Maternal imprinted gene, IGF2R, were fully methylated in both two oocytes. Furthermore, we also observed a positive correlation between gene expression and methylation level in gene body, but not in promoter regions.
In summary, we are the first to perform single-cell parallel M&T sequencing on a single human oocyte. The technique allows delineating the dynamics between epigenetic modification and transcriptional activity in parallel fashion. We demonstrated that the quality of transcriptome and methylome profiles are comparable to conventional single-cell transcriptome or methylome approach. We also showed the two single oocytes from the same donor exhibited a positive correlation between gene expression and methylation level on gene body region. The study therefore provides a foundation for the development of molecular diagnosis on oocyte quality.
Acceptance Date03/09/2017
All Author(s) ListTin-Lap, Lee, Yan Qian, Jinyue Liao, Wai-Yee Chan, Chi Ling, Grace Wing Shan Kong, Cathy Hoi Sze Chung, Tak Yeung Leung, Kevin Yuk-Lap Yip, King-Lau Chow, Tin Chiu Li
Name of ConferenceThe American Society of Human Genetics 2017 Annual Meeting
Start Date of Conference17/10/2017
End Date of Conference21/10/2017
Place of ConferenceOrlando
Country/Region of ConferenceUnited States of America
Year2017
Month10
LanguagesEnglish-United States

Last updated on 2018-08-11 at 12:10