Falchuk K H, Hardy C, Ulpino L, Vallee B L
Proc Natl Acad Sci U S A. 1978 Sep;75(9):4175-9. doi: 10.1073/pnas.75.9.4175.
The three major RNA classes from zinc-sufficient [(+Zn)] and zinc-deficient [(=Zn)] Euglena gracilis have been separated by affinity chromatography on oligo(dT)- and N-[N'-[m-(dihydroxyboryl)phenyl]succinamoyl]aminoethyl (DBAE)-celluloses. The total RNA content and the ribosomal and transfer RNA fractions are the same in (+Zn) and (=Zn) cells. IN (-Zn) cells, the messenger RNA fraction increases, and its altered base composition reveals additional bases and a 2-fold increase in the (G+C)/(A+U) ratio. Since the intracellular content of manganese increases in (-Zn) cells, we have examined its role in determining these changes in RNA composition. An increase in the Mn2+ content from 1 to 10 mM in assays with RNA polymerases I and II from (+Zn) cells and those with the single RNA polymerase from (-Zn) cells decreases the ratio of UMP to CMP incorporated from 1.7 to 1.0, 2.1 to 0.8 and 3.5 to 0.4, respectively. Thus, Mn2+ concentration can significantly alter the products of the enzymatic action of RNA polymerases from both (+Zn) and (-Zn) E. gracilis cells.
利用寡聚（dT）-纤维素和N-[N'-[间-（二羟基硼基）苯基]琥珀酰基]氨乙基（DBAE）-纤维素亲和层析法，分离了锌充足[（+Zn）]和锌缺乏[（-Zn）]的纤细裸藻的三类主要RNA。（+Zn）和（-Zn）细胞中的总RNA含量以及核糖体RNA和转移RNA组分相同。在（-Zn）细胞中，信使RNA组分增加，其碱基组成的改变显示出额外的碱基，并且（G+C）/（A+U）比值增加了2倍。由于（-Zn）细胞中锰的细胞内含量增加，我们研究了其在决定RNA组成这些变化中的作用。在使用来自（+Zn）细胞的RNA聚合酶I和II以及来自（-Zn）细胞的单一RNA聚合酶进行的测定中，将Mn2+含量从1 mM增加到10 mM，分别使掺入的UMP与CMP的比值从1.7降至1.0、从2.1降至0.8以及从3.5降至0.4。因此，Mn2+浓度可显著改变来自（+Zn）和（-Zn）纤细裸藻细胞的RNA聚合酶的酶促作用产物。
