Oocytes of a single individual of Halocynthia roretzi (Aomori, Japan) were fertilized by sperms of an another single individual and development was followed microscopically. Embryos were snapfrozen in liquid nitrogen at the appropriate stage and kept at -80°C. Total RNA was prepared with the AGPC method and the quality was checked with the Bioanalyzer, most samples had a RIN value of higher than 9. Strand specific libraries were constructed and the sequencing (50PE) was performed with Illumina HiSeq 2000 technology (BGI, Hong Kong, China).

WT Halocynthia roretzi egg probed for Suz12 expression, a member of the PRC2 complex that catalyzes H3K27me3.
Suz12 is expressed at a high level in eggs.

WT Halocynthia roretzi 8-cell stage embryo probed for Suz12 expression, a member of the PRC2 complex that catalyzes H3K27me3.
Suz12 is expressed in the whole embryo.
Original comment:Suz12 has more transcripts in the animal than vegetal hemispheres from the 8-cell to the 110-cell stage.

Animal (left) and vegetal (right) views of a WT Halocynthia roretzi 16-cell stage embryo probed for Suz12 expression, a member of the PRC2 complex that catalyzes H3K27me3.
Suz12 is expressed in the whole embryo.
Original comment:Suz12 has more transcripts in the animal than vegetal hemispheres from the 8-cell to the 110-cell stage.

Animal view of a WT Halocynthia roretzi 32-cell stage embryo probed for Suz12 expression, a member of the PRC2 complex that catalyzes H3K27me3.
Suz12 is expressed in the whole embryo.
Original comment:Suz12 has more transcripts in the animal than vegetal hemispheres from the 8-cell to the 110-cell stage.
Black arrows indicate germline cells without distinct signals.

Animal view of a WT Halocynthia roretzi 64-cell stage embryo probed for Suz12 expression, a member of the PRC2 complex that catalyzes H3K27me3.
Suz12 is expressed in the whole embryo.
Original comment:Suz12 has more transcripts in the animal than vegetal hemispheres from the 8-cell to the 110-cell stage and showed no enrichment of mRNAs in germline cells at later stages (at the 64- and 110-cell stages; black arrows) when increased levels of H3K27me3 were observed.

Animal (left) and vegetal (right) views of a WT Halocynthia roretzi 110-cell stage embryo probed for Suz12 expression, a member of the PRC2 complex that catalyzes H3K27me3.
Suz12 is expressed in the animal hemisphere, in most of B-line blastomers and A-line in nerve cord precursors.
Original comment:Suz12 has more transcripts in the animal than vegetal hemispheres from the 8-cell to the 110-cell stage and showed no enrichment of mRNAs in germline cells at later stages (at the 64- and 110-cell stages; black arrows) when increased levels of H3K27me3 were observed.