RT-PCR analysis. A and B, Gel figures presenting confirmatory RT-PCR analysis for a gene highly expressed in pollen but not detected in sperm cells in our microarray analysis, encoding a carbonic anhydrase family protein (At5g44340; A); and genes involved in the sRNAs and RdDM pathways, which are not detectable in sperm cells, DCL3 (At3g43920), CMT3 (At1g69770), and NRPD2a (At3g23780; B). C, RT-PCR on total RNA from two samples of FACS-isolated sperm cells (SC#1, SC#2), pollen, and leaf, showing enrichment of MGH3 (At1g19890) transcripts and absence of VEX1 (At5g62850) transcripts in both sperm cell replicates. D, Expression of several genes presented in was tested by RT-PCR in sperm cells, pollen, seedling, ovule, and silique cDNA samples. TUB4 (At5g04180) was used as positive control. SC, Sperm cells; G, genomic DNA.