Animals interact with their environments all the time,and must react to all kinds of factors present in the environments.Environmental RNA interference refers to the phenomenon that exogenous RNA molecules can enter cells of certain animal species and interfere with gene expression of these animals.These exogenous RNAs may be molecules in animal food,or may be present in the living environment from other sources.Molecular pathways for the cell entry of environmental RNAs and further for their functionality in gene interference have started to be revealed in the animal model Caenorhabditis elegans.Here we highlight some known examples of environmental RNA interference(RNAi)in animals and introduce the molecular mechanisms underneath.
MENG LingFengCHEN LiangLI ZhaoYongWU ZhengXingSHAN Ge
A major portion of the mammalian genome is transcribed to produce large numbers of noncoding RNAs(ncRNAs).During the past decade,the discovery of small RNAs,including the microRNAs(miRNA) and small interfering RNAs(siRNA),has led to important advances in biology.The breadth of the ncRNA field of study has substantially expanded and many recent results have revealed a range of functions that can be attributed to the miRNAs and other ncRNAs.For example,H19 RNA,HOTAIR RNA,transcribed ultraconserved regions(T-UCRs),natural antisense RNA,transfer RNA and mitochondrial noncoding RNA have been suggested to play important roles in cancers and other diseases as well as in diverse cellular processes.In this review,we focus on the current status of several classes of ncRNAs associated with cancer with the emphasis on those that are not microRNAs.
