Kuligowski J, Ferrand M, Chenou E
Université Pierre et Marie Curie, Laboratoire de Biologie de la Reproduction des Végétaux, Paris, France.
Mol Reprod Dev. 1991 Sep;30(1):27-33. doi: 10.1002/mrd.1080300104.
In early embryos of the fern Marsilea vestita, we have shown that transcription did not begin until the 8-cell stage, even though protein synthesis was taking place. As in animal species, the pre-existence of stored maternal mRNA has been suspected in embryonic cells. To investigate the presence of such long-lived mRNA we have used in situ hybridization method using [3H]polyuridylic acid, [3H]poly(U), as a probe. Temporal and spatial changes in the distribution of poly(A)+ RNA were followed throughout all the different phases of embryogenesis. Poly(A)+ RNA was present in the cytoplasm of both unfertilized and fertilized eggs and early embryos, while the nucleus exhibited no, or a moderate, [3H]-poly(U) binding activity. New poly(A)+ RNA was detected in the nucleus only at the 16-cell stage, when cytological differentiation of the root apical cell became morphologically detectable. After in situ hydridization with the labeled probes, the numerous silver grains detected autoradiographically over the mature sperm, indicate the presence of poly(A)+ RNA molecules associated with the male genome. We discuss the possible role of poly(A)+ RNA of maternal origin in supporting early translation prior to synthesis of new mRNA. Additional studies are needed to elucidate the role of stored paternal mRNA.
在水蕨（Marsilea vestita）的早期胚胎中，我们已经表明，即使蛋白质合成正在进行，转录直到8细胞阶段才开始。与动物物种一样，胚胎细胞中一直怀疑存在预先储存的母体mRNA。为了研究这种长寿命mRNA的存在，我们使用了以[3H]多聚尿苷酸（[3H]poly(U)）作为探针的原位杂交方法。在胚胎发生的所有不同阶段，跟踪了多聚腺苷酸（poly(A)+）RNA分布的时空变化。未受精卵、受精卵和早期胚胎的细胞质中都存在poly(A)+ RNA，而细胞核则没有或仅有适度的[3H]-poly(U)结合活性。仅在16细胞阶段，当根尖细胞的细胞学分化在形态上可检测到时，才在细胞核中检测到新的poly(A)+ RNA。用标记探针进行原位杂交后，在成熟精子上通过放射自显影检测到的大量银颗粒，表明存在与雄性基因组相关的poly(A)+ RNA分子。我们讨论了母体来源的poly(A)+ RNA在新mRNA合成之前支持早期翻译的可能作用。需要进一步的研究来阐明储存的父本mRNA的作用。
