Leach R A, Tuck M T
Department of Biological Sciences, Ohio University, Athens, OH45701, USA.
Int J Biochem Cell Biol. 2001 Oct;33(10):984-99. doi: 10.1016/s1357-2725(01)00071-1.
Ribonuclease protection assays (RPA) were used to detect and quantitate the amount of messenger RNA (mRNA) coding for the S-adenosyl-L-methionine binding subunit (MT-A70) of the mRNA (N6-adenosine)-methyltransferase from different types of cultured cells. HeLa cells cultured in suspension were analyzed at regular intervals along a normal growth curve. It was discovered that MT-A70 mRNA was transcribed constitutively across the time-course, irrespective of the rate of cellular proliferation. Further, 11 different cell lines representing non-tumorigenic, tumorigenic, and virally-transformed tumorigenic types from Homo sapiens, Mus musculus, and Rattus norvegicus were examined for MT-A70 mRNA expression. It was found that all the cell lines expressed a long and short splice-variant form of the gene. In general, the cell lines expressed a similar total amount of the MT-A70 mRNA while statistically significant differences existed between the quantity of the long and short forms among cell types. Tumorigenic cell lines synthesized as much as a 9-fold greater amount of long form versus short form MT-A70 mRNA. Comparatively, non-tumorigenic cell lines generally expressed only a 1.5-fold greater amount of long form versus short form MT-A70 mRNA.
核糖核酸酶保护分析（RPA）用于检测和定量来自不同类型培养细胞的信使核糖核酸（mRNA）（N6-腺苷）-甲基转移酶的S-腺苷-L-甲硫氨酸结合亚基（MT-A70）编码的信使核糖核酸（mRNA）的量。对悬浮培养的HeLa细胞沿正常生长曲线定期进行分析。结果发现，MT-A70 mRNA在整个时间进程中持续转录，与细胞增殖速率无关。此外，对代表来自智人、小家鼠和褐家鼠的非致瘤性、致瘤性和病毒转化致瘤性类型的11种不同细胞系进行了MT-A70 mRNA表达检测。发现所有细胞系均表达该基因的长剪接变体形式和短剪接变体形式。总体而言，细胞系表达的MT-A70 mRNA总量相似，而细胞类型之间长形式和短形式的数量存在统计学上的显著差异。致瘤性细胞系合成的长形式MT-A70 mRNA比短形式多9倍。相比之下，非致瘤性细胞系通常表达的长形式MT-A70 mRNA仅比短形式多1.5倍。
