Kan J L, Moran R G
Department of Pharmacology and Toxicology and the Massey Cancer Center, Medical College of Virginia, Virginia Commonwealth University, Richmond, VA 23298-0230, USA.
Nucleic Acids Res. 1997 Aug 1;25(15):3118-23. doi: 10.1093/nar/25.15.3118.
The mouse glycinamide ribonucleotide formyltransferase (GART) locus is known to produce two functional proteins, one by recognition and use of an intronic polyadenylation site and the other by downstream splicing. We now report a similar intronic polyadenylation mechanism for the human GART locus. The human GART gene has two potential polyadenylation signals within the identically located intron as that involved in intronic polyadenylation in the mouse gene. Each of the potential polyadenylation signals in the human gene was followed by an extensive polyT rich tract, but only the downstream signal was preceded by a GT tract. Only the downstream signal was utilized. The polyT rich tract which followed the functional polyadenylation site in the human GART gene was virtually identical in sequence to a similarly placed region in the mouse gene. An exact inverted complement to the polyT rich stretch following the active polyadenylation signal was found in the upstream intron of the human gene, suggesting that a hairpin loop may be involved in this intronic polyadenylation.
已知小鼠甘氨酰胺核糖核苷酸甲酰基转移酶（GART）基因座可产生两种功能性蛋白质，一种是通过识别和利用内含子聚腺苷酸化位点产生的，另一种是通过下游剪接产生的。我们现在报道人类GART基因座存在类似的内含子聚腺苷酸化机制。人类GART基因在与小鼠基因内含子聚腺苷酸化所涉及的内含子位置相同的区域内有两个潜在的聚腺苷酸化信号。人类基因中的每个潜在聚腺苷酸化信号后面都有一个富含多聚T的区域，但只有下游信号前面有一个GT序列。只有下游信号被利用。人类GART基因中功能性聚腺苷酸化位点后面的富含多聚T的区域在序列上与小鼠基因中类似位置的区域几乎相同。在人类基因的上游内含子中发现了与活性聚腺苷酸化信号后面的富含多聚T的片段完全反向互补的序列，这表明发夹环可能参与了这种内含子聚腺苷酸化过程。
