HETEROGENEITY AND 5'-TERMINAL STRUCTURES OF THE LATE RNAS OF SIMIAN-VIRUS-40
HETEROGENEITY AND 5'-TERMINAL STRUCTURES OF THE LATE RNAS OF SIMIAN-VIRUS-40
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DOI：
10.1016/0022-2836(78)90022-0
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发表时间：
1978-01-01
影响因子：
5.6
通讯作者：
WEISSMAN, SM
中科院分区：
文献类型：
--
作者：
GHOSH, PK;REDDY, VB;WEISSMAN, SM
SV-40晚期裂解RNA的5“-末端结构通过将5”-末端位置用32 P标记的小DNA片段的正链与细胞质多聚腺苷酸化晚期RNA的特定区域结合，用逆转录酶将这些引物片段在3“-方向延伸，在变性聚丙烯酰胺凝胶上分离延伸产物，并对延伸产物进行DNA序列分析。延伸与19 S RNA体的5“末端结合的引物，显示出多种延伸产物。产生这些产物的RNA分为4类，第一类含有与SV-40 DNA共线的序列，后3类含有将19 S体5“末端残基476（0.765图单位）分别与残基444、291和212融合的剪接。在分析的15个延伸产物中，8个具有3“末端，序列为T-A（A）。这些末端位于SV-40基因组上的位置243、182、110、55和5189。许多证据，包括体内标记的晚期RNA的核苷酸序列分析和SV-40晚期mRNA中邻近加帽结构的主要序列是A-U（U）的事实，表明243和182位的末端对应于体内离散的19 S RNA的5“末端，并且在较短位置处终止的末端也可能对应于19 S RNA的体内特异性种类。观察到一个额外的延伸产物，其序列与SV-40 DNA共线，T-A-A的3“末端在redidue 548（0.779图谱单位）处。它含有与VP[病毒多肽]3互补的序列，但不包含19 S RNA的VP 2起始密码子，以及在SV-40的16 S晚期和19 S早期RNA中分析的4个额外缺口，相同的二、三或四核苷酸序列位于无缺口前体上进行剪接的位点;这些序列可能参与决定剪接反应的特异性。
The 5''-terminal structures of the late lytic RNA of SV-40 were investigated by binding the plus strand of small DNA fragments labeled in the 5''-terminal position with 32P to specific regions of cytoplasmic polyadenylated late RNA, extending these primer fragments in a 3'' direction with reverse transcriptase, fractionating the extended products on denaturing polyacrylamide gels and preforming DNA sequence analyses of the extended products. Extension of a primer bound to the 5'' terminus of the body of 19 S RNA revealed a multiplicity of extended products. RNA from which these products are derived fall into 4 classes, the first containing sequences colinear with SV-40 DNA and the latter 3 containing splices which fuse the 5'' terminus of the 19 S body at residue 476 (0.765 map units) to residues 444, 291 and 212, respectively. Of 15 extended products analyzed, 8 have 3'' termini with the sequence T-A(A). These termini lie at positions 243, 182, 110, 55 and 5189 on the SV-40 genome. A number of lines of evidence, including nucleotide sequence analysis of late RNA labeled in vivo and the fact that the principal sequence in SV-40 late mRNA adjacent to capped structures is A-U(U), suggest that the termini at positions 243 and 182 correspond to the 5'' termini of discrete in vivo 19 S RNA and that stops at the shorter positions may also correspond to the 5'' termini of specific in vivo species of 19 S RNA. An additional extended product was observed with a sequence colinear with SV-40 DNA and a 3'' terminus of T-A-A at redidue 548 (0.779 map units). It contains sequences complementary to the VP[viral polypeptide]3 but not the VP2 initiation codons of 19 S RNA, and 4 additional gaps analyzed in the late 16 S and early 19 S RNA of SV-40, identical di-, tri- or tetranucleotide sequences lie on the ungapped precursor at sites which undergo splicing; these sequences may be involved in determining the specificity of the splicing reaction.