Boursnell M E, Brown T D, Foulds I J, Green P F, Tomley F M, Binns M M
J Gen Virol. 1987 Jan;68 ( Pt 1):57-77. doi: 10.1099/0022-1317-68-1-57.
The nucleotide sequence determination of the genome of the Beaudette strain of the coronavirus avian infectious bronchitis virus (IBV) has been completed. The complete sequence has been obtained from 17 overlapping cDNA clones, the 5'-most of which contains the leader sequence (as determined by direct sequencing of the genome) and the 3'-most of which contains the poly(A) tail. Approximately 8 kilobases at the 3' end of this sequence have already been published. These contain the sequences of mRNAs A to E within which are the genes for the spike, the membrane and the nucleocapsid polypeptides: the main structural components of the virion. The remainder of the sequence, equivalent to the 'unique' region of mRNA F, is some 20 kilobases in length and is thought to code for a polymerase or polymerases which are involved in the replication of the genome and the production of the subgenomic messenger RNAs. This sequence contains two large open reading frames, potentially coding for polypeptides of molecular weights 441,000 and 300,000. Unlike other large open reading frames in the virus, the 300,000 open reading frame appears to have no subgenomic RNA associated with it which would allow it to be at the 5' end of an mRNA species. Because of this, and because of the characteristics of the sequence in the region immediately upstream of its start codon, other mechanisms of translation, such as ribosome slippage, must be postulated.
禽传染性支气管炎病毒（IBV）博德特毒株的基因组核苷酸序列测定已完成。完整序列是从17个重叠的cDNA克隆中获得的，其中最靠近5'端的克隆包含前导序列（通过基因组直接测序确定），最靠近3'端的克隆包含聚腺苷酸尾。该序列3'端约8千碱基已发表。这些包含mRNA A至E的序列，其中有编码刺突、膜和核衣壳多肽的基因：病毒粒子的主要结构成分。序列的其余部分相当于mRNA F的“独特”区域，长度约为20千碱基，被认为编码参与基因组复制和亚基因组信使RNA产生的一种或多种聚合酶。该序列包含两个大的开放阅读框，可能编码分子量分别为441,000和300,000的多肽。与病毒中的其他大开放阅读框不同，300,000的开放阅读框似乎没有与之相关的亚基因组RNA，使其处于mRNA种类的5'端。因此，由于其起始密码子上游紧邻区域序列的特征，必须假定其他翻译机制，如核糖体移码。
