Anzai K, Kobayashi S, Suehiro Y, Goto S
Brain Res. 1987 Apr;388(1):43-9. doi: 10.1016/0169-328x(87)90019-2.
Two cDNA clones for mouse brain-specific small RNA were isolated, whose sequences turn out to be highly homologous to that of a genomic mouse ID-like clone isolated previously. By use of one of these cDNA clones as a probe, the copy numbers of ID-related sequences in several mammalian species were determined. The ID sequence was found to be conserved in mice, rats, hamsters and guinea pigs, but not in non-rodent species. There were about 3 orders of magnitude of difference in the copy numbers of the gene, i.e. rat 4.0 X 10(4), mouse 4.5 X 10(2), hamster 1.5 X 10(2), and guinea pig less than 50. The gene was transcribed as small RNA in the brain of rodent species. The relative concentration of small RNA in the brain was roughly proportional to the copy number of the ID sequence in mice, hamsters, and probably in guinea pigs also. On the other hand, the amount of the RNA in rat brain was much less than that expected from the large copy number of the gene. On the basis of these observations, the possibility is discussed that most of the ID sequences in the rat are pseudogenes.
分离出了两个小鼠脑特异性小RNA的cDNA克隆，其序列与先前分离出的一个基因组小鼠ID样克隆的序列高度同源。通过使用其中一个cDNA克隆作为探针，测定了几种哺乳动物物种中ID相关序列的拷贝数。发现ID序列在小鼠、大鼠、仓鼠和豚鼠中保守，但在非啮齿动物物种中不保守。该基因的拷贝数存在约3个数量级的差异，即大鼠4.0×10⁴、小鼠4.5×10²、仓鼠1.5×10²，豚鼠少于50。该基因在啮齿动物物种的脑中转录为小RNA。小鼠、仓鼠以及可能还有豚鼠脑中的小RNA相对浓度与ID序列的拷贝数大致成比例。另一方面，大鼠脑中RNA的量远低于从该基因的大量拷贝数所预期的量。基于这些观察结果，讨论了大鼠中大多数ID序列是假基因的可能性。
