对从由海水样品提取出的物质获得的环境DNA 和RNA序列所做的计算分析，显示了丰富的细菌非编码RNA（ncRNA）的存在，它们在大小和复杂性上很像大型核糖酶。人们特别感兴趣的是两种新发现的RNA，被称为GOLLD 和 HEARO，它们是迄今所发现的最大、最复杂的RNA之一。这些发现表明，在水中、土壤中和尚未探索的其他环境中，存在很多有待发现的具有超大尺寸、复杂结构或其他特别之处的RNA。（生物谷Bioon.com）
生物谷推荐原始出处：
Nature 462, 656-659 (3 December 2009) | doi:10.1038/nature08586
Exceptional structured noncoding RNAs revealed by bacterial metagenome analysis
Zasha Weinberg1,2, Jonathan Perreault2, Michelle M. Meyer2 & Ronald R. Breaker1,2,3
1 Howard Hughes Medical Institute,
2 Department of Molecular, Cellular and Developmental Biology,
3 Department of Molecular Biophysics and Biochemistry, Yale University, Box 208103, New Haven, Connecticut 06520-8103, USA
Correspondence to: Ronald R. Breaker1,2,3 Correspondence and requests for materials should be addressed to R.R.B.
Estimates of the total number of bacterial species1, 2, 3 indicate that existing DNA sequence databases carry only a tiny fraction of the total amount of DNA sequence space represented by this division of life. Indeed, environmental DNA samples have been shown to encode many previously unknown classes of proteins4 and RNAs5. Bioinformatics searches6, 7, 8, 9, 10 of genomic DNA from bacteria commonly identify new noncoding RNAs (ncRNAs)10, 11, 12 such as riboswitches13, 14. In rare instances, RNAs that exhibit more extensive sequence and structural conservation across a wide range of bacteria are encountered15, 16. Given that large structured RNAs are known to carry out complex biochemical functions such as protein synthesis and RNA processing reactions, identifying more RNAs of great size and intricate structure is likely to reveal additional biochemical functions that can be achieved by RNA. We applied an updated computational pipeline17 to discover ncRNAs that rival the known large ribozymes in size and structural complexity or that are among the most abundant RNAs in bacteria that encode them. These RNAs would have been difficult or impossible to detect without examining environmental DNA sequences, indicating that numerous RNAs with extraordinary size, structural complexity, or other exceptional characteristics remain to be discovered in unexplored sequence space.
