未能在来自HeLa细胞的线粒体DNA编码的含聚腺苷酸（poly(A)）RNA中检测到“帽”结构。

Grohmann K, Amairic F, Crews S, Attardi G

Nucleic Acids Res. 1978 Mar;5(3):637-51. doi: 10.1093/nar/5.3.637.

The structure of the 5'-termini has been investigated in mitochondrial DNA-coded poly(A)-containing RNA from HeLa cells. For this purpose, mitochondrial RNA isolated from cells labeled for 3 hours with [32P]orthophosphate in the presence of 20 microgram/ml camptothecin, and selected for poly(A) content by two passages through oligo(dT)-cellulose, was digested either with the nuclease P1 or with a mixture of RNases: the digestion products were then fractionated by two-dimensional electrophoresis. No "cap" structures were detected under conditions where the presence of such structures in one out of five to ten RNA molecules would have been recognized. It is, therefore, likely that "cap" structures are completely absent in HeLa cell mitochondrial poly(A)-containing RNA.

人们对来自HeLa细胞的线粒体DNA编码的含聚腺苷酸（poly(A)）的RNA的5'末端结构进行了研究。为此，从在20微克/毫升喜树碱存在下用[32P]正磷酸盐标记3小时的细胞中分离出线粒体RNA，并通过两次过寡聚（dT）纤维素柱选择富含poly(A)的RNA，然后用核酸酶P1或核糖核酸酶混合物进行消化：消化产物随后通过二维电泳进行分离。在五到十个RNA分子中有一个存在此类结构就会被识别的条件下，未检测到“帽”结构。因此，HeLa细胞线粒体含poly(A)的RNA中很可能完全不存在“帽”结构。