Most sea urchin maternal mRNA sequences in every abundance class appear in both polyadenylated and nonpolyadenylated molecules.
Most sea urchin maternal mRNA sequences in every abundance class appear in both polyadenylated and nonpolyadenylated molecules.
复制标题
大多数海胆母体 mRNA 序列在每个丰度类别中都出现在聚腺苷酸化和非聚腺苷酸化分子中。
DOI：
10.1016/0012-1606(81)90164-0
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发表时间：
1981
影响因子：
2.7
通讯作者：
T. Humphreys
中科院分区：
文献类型：
--
作者：
R. Duncan;T. Humphreys
采用cDNA杂交和单拷贝基因组DNA杂交的方法，分析了海胆卵中积累的含多聚(A)和缺乏多聚(A) RNA的序列。聚(A)卵RNA与其同源cDNA的反应发生在5个r0t上。标准的计算机拟合反应曲线显示了三个丰度等级，poly(A) RNA在高丰度序列中占32%，中等丰度序列中占13%，稀有序列中占55%。计算出的这些类别中平均大小、3000个核苷酸长的mRNA序列的数量分别为2,44和4600。cDNA与总RNA和poly(A)缺陷RNA的反应表明，含有任何单个序列的分子中，只有不到一半的分子携带足够大的poly(A)片段以结合oligo（dT）。与卵RNA互补的单拷贝DNA的饱和杂交表明，所有罕见的类序列都是聚腺苷化的。大约三分之一的分子有30%到50%的腺苷化；剩下的罕见序列在大约5%的分子上被聚腺苷化。大多数存在于卵子中的聚(A) RNA分子中的序列被发现与受精后的多聚体有关。在与海胆总DNA还原的cDNA中，约80 ~ 85%的poly(A)母源mRNA序列为单拷贝序列，15% ~ 20%为重复序列。
The sequences in poly(A)-containing and -deficient RNA accumulated in sea urchin eggs were analyzed by hybridization to cDNA and single-copy genomic DNA. The reaction of poly(A) egg RNA to its homologous cDNA occurs over five orders ofR0t. A standard computer fit to the reaction curves indicates three abundance classes with 32% of the poly(A) RNA in highly abundant sequences, 13% in moderately abundant sequences, and 55% in rare sequences. The calculated number of averaged-sized, 3000-nucleotide-long mRNA sequences in each of these classes was 2, 44, and 4600, respectively. Reactions of cDNA to total and poly(A)-deficient RNA indicate that less than half of the molecules containing any individual sequence carried a poly(A) segment large enough to bind to oligo(dT). A saturation hybridization to single-copy DNA complementary to egg RNA indicated that all rare class sequences are polyadenylated. About one-third are adenylated on 30 to 50% of their molecules; the remaining rare sequences are polyadenylated on about 5% of their molecules. Most sequences present in poly(A) RNA molecules in the egg are found associated with polysomes following fertilization. About 80 to 85% of the poly(A) maternal mRNA sequences in cDNA which reanneal to total sea urchin DNA react as-single-copy sequences, while 15 to 20% react as repetitive DNA sequences.