Harding R M, Burns T M, Hafner G, Dietzgen R G, Dale J L
Centre for Molecular Biotechnology, Queensland University of Technology, Brisbane, Australia.
J Gen Virol. 1993 Mar;74 ( Pt 3):323-8. doi: 10.1099/0022-1317-74-3-323.
One DNA component of the banana bunchy top virus (BBTV) genome was cloned and sequenced. This component is present as a circular, ssDNA in the virions and consists of 1111 nucleotides. It contains one large open reading frame (ORF) of 858 nucleotides in the virion sense; this ORF encodes a putative replicase based on the presence of a dNTP-binding motif (GGEGKT). Two smaller ORFs (249 and 366 nucleotides), in the complementary orientation, could not be assigned any obvious function. Neither of these ORFs had significant sequence homology with any known DNA plant virus gene or gene product. Computer analysis of this component-predicted a strong stem-loop structure in the virion sense putative untranslated region; a nonanucleotide sequence in the loop was nearly identical to the nonanucleotide invariant loop sequence of geminiviruses and coconut foliar decay virus. There is strong evidence that the genome of BBTV consists of more than one component because no ORF was found that would encode a protein the size of the BBTV coat protein. BBTV has some characteristics in common with geminiviruses but cannot be classified as one. Rather, BBTV probably belongs to an undescribed plant virus group which could also include subterranean clover stunt virus and coconut foliar decay virus.
香蕉束顶病毒（BBTV）基因组的一个DNA组分被克隆并测序。该组分在病毒粒子中以环状单链DNA形式存在，由1111个核苷酸组成。它在病毒粒子链中有一个858个核苷酸的大开放阅读框（ORF）；基于存在一个dNTP结合基序（GGEGKT），这个ORF编码一种假定的复制酶。两个较小的ORF（249和366个核苷酸），呈互补方向，无法赋予任何明显的功能。这些ORF与任何已知的DNA植物病毒基因或基因产物均无显著的序列同源性。对该组分的计算机分析预测，在病毒粒子链假定的非翻译区有一个强茎环结构；环中的一个九核苷酸序列与双生病毒和椰子叶腐烂病毒的九核苷酸不变环序列几乎相同。有强有力的证据表明，BBTV的基因组由不止一个组分组成，因为未发现能编码BBTV外壳蛋白大小的蛋白质的ORF。BBTV与双生病毒有一些共同特征，但不能归类为双生病毒。相反，BBTV可能属于一个未描述的植物病毒组，该组可能还包括地下三叶草矮化病毒和椰子叶腐烂病毒。
