Changes in poly(A) RNA and TMG snRNA distribution in the embryo sac of Hyacinthus orientalis L. before and after fertilization

Abstract: The content and distribution of the poly(A) RNA and splicing machinery element––TMG snRNA in cells of the Hyacinthus orientalis L. mature embryo sac, during the progamic phase and after fertilization, were investigated. Using fluorescence in situ hybridization and immunofluorescence methods we showed that in the mature unfertilized embryo sac strong signal indicating poly(A) RNA and TMG snRNA appeared only in synergids and antipodal cells. In synergids accumulation of poly(A) RNA was shown in cytoplasm around the filiform apparatus. In the egg cell and central cell of the embryo sac accumulation of poly(A) RNA was very low and only low pool of TMG snRNA was observed in the nuclei of these cells. During the progamic phase, dramatic changes in the accumulation and distribution of poly(A) RNA and TMG snRNA were observed in the synergids. In these cells a considerable decrease in accumulation of TMG snRNA in the nucleus and poly(A) RNA in the region of the filiform apparatus occurred. In the egg cell and central cell the content of polyadenylated transcripts and TMG snRNA was still low. After fertilization a drastic increase in polyadenylated transcripts and TMG snRNA content was observed in the cells which undergo a fusion with the sperm cells (the zygote and the fertilized central cells). In contrast, a progressive decrease in poly(A) RNA and splicing snRNAs accumulation was observed in degenerating antipodal cells and synergids.