Isolation, X location and activity of the marsupial homologue of SLC16A2, an XIST-flanking gene in eutherian mammals
Isolation, X location and activity of the marsupial homologue of SLC16A2, an XIST-flanking gene in eutherian mammals
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DOI：
10.1007/s10577-005-1006-5
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发表时间：
2005-10-01
影响因子：
2.6
通讯作者：
Graves, JAM
中科院分区：
文献类型：
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作者：
Koina, E;Wakefield, MJ;Graves, JAM
X染色体失活(XCI)实现了真核哺乳动物中大多数X连锁基因的雄性和雌性之间的剂量补偿。这是一种受XIST基因控制的全染色体效应，尽管有些基因逃脱了失活。有袋类的XCI不同于真兽类的XCI过程，暗示在两个谱系的进化过程中XCI机制发生了根本性的变化。没有直接证据表明存在有袋类XIST同源基因。XCI只在任何有袋类动物中被研究过一小部分基因，而在模式袋鼠Macropus eugenii(袋鼠)中没有。因此，我们研究了人类和小鼠X染色体上XIST侧翼的SLC16A2基因(溶质携带者，家族16，A类，成员2)的序列、定位和活性。一个含有有袋类SLC16A2的BAC克隆被定位在Tammar X染色体长臂的末端，并用于RNA FISH实验，以确定一个或两个基因座在雌性细胞中转录。在雄性和雌性细胞中，只发现了一个信号，表明有袋类SLC16A2基因在失活的X上是沉默的。
X chromosome inactivation (XCI) achieves dosage compensation between males and females for most X-linked genes in eutherian mammals. It is a whole-chromosome effect under the control of the XIST locus, although some genes escape inactivation. Marsupial XCI differs from the eutherian process, implying fundamental changes in the XCI mechanism during the evolution of the two lineages. There is no direct evidence for the existence of a marsupial XIST homologue. XCI has been studied for only a handful of genes in any marsupial, and none in the model kangaroo Macropus eugenii (the tammar wallaby). We have therefore studied the sequence, location and activity of a gene SLC16A2 (solute carrier, family 16, class A, member 2) that flanks XIST on the human and mouse X chromosomes. A BAC clone containing the marsupial SLC16A2 was mapped to the end of the long arm of the tammar X chromosome and used in RNA FISH experiments to determine whether one or both loci are transcribed in female cells. In male and female cells, only a single signal was found, indicating that the marsupial SLC16A2 gene is silenced on the inactivated X.