Eiden J J
Department of Pediatrics, Johns Hopkins University School of Medicine, Baltimore, Maryland 21205.
Virology. 1994 Feb 15;199(1):212-8. doi: 10.1006/viro.1994.1113.
The seventh genomic segment of the IDIR strain of group B rotavirus was cloned, sequenced, and expressed in vitro in order to evaluate the gene coding assignment by comparison with group A rotaviruses (GAR). Viral genomic RNA for these reactions was obtained directly from fecal specimens of infected infant rats. IDIR virus gene 7 (IDIRg7) contained 1276 bp. Both 5' and 3' termini resembled those reported for other IDIR virus genomic segments. Two open reading frames (ORF) were predicted from the gene sequence: a long ORF from bases 258-1217 and a short ORF from bases 41-385. The first AUG of the long ORF was flanked by sequences associated with highly efficient translation, but less efficient translation was predicted for the short ORF. In vitro transcription and translation of IDIRg7 demonstrated a product consistent with polypeptide synthesis from the long ORF but not the short ORF. Convalescent rat antibody directed against the IDIR agent specifically immunoprecipitated the IDIRg7 protein and indicated that the in vitro translation product was indeed encoded by the virus genome. Thus, the untranslated 5' region of IDIRg7 was longer than that previously described for any major rotavirus product. Comparison of the IDIRg7 sequence indicated 51% similarity and 18% identity with the amino acid residues of NS53 of the SA11 strain of GAR. However, the sequence of IDIRg7 did not share the putative zinc binding region postulated for NS53 of rotavirus groups A and C. It will be of interest in future experiments to evaluate the function of the IDIRg7 product following large-scale synthesis by alternative expression systems such as vaccinia or baculovirus.
为了通过与A组轮状病毒（GAR）比较来评估基因编码分配，对B组轮状病毒IDIR株的第七个基因组片段进行了克隆、测序和体外表达。这些反应所需的病毒基因组RNA直接从感染幼鼠的粪便标本中获得。IDIR病毒基因7（IDIRg7）包含1276个碱基对。5'和3'末端与其他IDIR病毒基因组片段报道的相似。从基因序列预测出两个开放阅读框（ORF）：一个长ORF位于碱基258 - 1217，一个短ORF位于碱基41 - 385。长ORF的第一个AUG两侧是与高效翻译相关的序列，但预测短ORF的翻译效率较低。IDIRg7的体外转录和翻译显示出一种与长ORF而非短ORF的多肽合成一致的产物。针对IDIR病原体的恢复期大鼠抗体特异性免疫沉淀了IDIRg7蛋白，并表明体外翻译产物确实由病毒基因组编码。因此，IDIRg7的非翻译5'区域比先前描述的任何主要轮状病毒产物的都要长。IDIRg7序列与GAR的SA11株NS53的氨基酸残基相比，相似性为51%，同一性为18%。然而，IDIRg7的序列并不具有轮状病毒A组和C组NS53假定的锌结合区域。在未来的实验中，通过痘苗或杆状病毒等替代表达系统大规模合成IDIRg7产物后评估其功能将是有意义的。
