Changes in rat pituitary nuclear and cytoplasmic pro-opiomelanocortin RNAs associated with adrenalectomy and glucocorticoid replacement.
Changes in rat pituitary nuclear and cytoplasmic pro-opiomelanocortin RNAs associated with adrenalectomy and glucocorticoid replacement.
复制标题
与肾上腺切除术和糖皮质激素替代相关的大鼠垂体核和细胞质阿黑皮质素原 RNA 的变化。
DOI：
10.1016/0303-7207(89)90029-4
复制
发表时间：
1989
影响因子：
4.1
通讯作者：
Roberts,JL
中科院分区：
文献类型：
--
作者：
Autelitano,DJ;Blum,M;Roberts,JL
虽然糖皮质激素操纵对垂体前阿黑皮素（POMC）基因的转录影响已被记录，但尚不清楚糖皮质激素是否激活额外的转录后机制来调节POMC基因表达。我们已经使用了RNA探针，跨越外显子/内含子交界处的敏感的核酸酶保护试验，以检查POMC前体RNA的变化，以及成熟的mRNA在细胞核和细胞质后肾上腺切除术（ADX）和外源性糖皮质激素的管理。ADX导致前叶（AL）中POMC初级转录物水平的快速和持续的8- 10倍增加，从ADX后1 - 14天。细胞核中成熟POMC mRNA的刺激也很快，ADX后1天明显增加7至8倍。与此形成鲜明对比的是，POMC mRNA在细胞质中的时间依赖性积累比较缓慢，在ADX后1天达到比假手术动物高约2倍的水平，在ADX后14天达到高12倍的水平。尽管核POMC前体RNA水平不断升高，但ADX后促肾上腺皮质激素细胞质中POMC mRNA的积累速率不是线性的，最大增加发生在ADX后的前1-4天内。这导致改变的摩尔比POMC初级转录：核mRNA：细胞质mRNA的AL在ADX后1和4天，并显示了相对增加的比例POMC RNA转录核内。对ADX大鼠急性给予地塞米松导致AL中POMC初级转录水平的快速80-90%抑制，其在30分钟时达到最大，但成熟mRNA没有相关变化。在这些研究中，在神经中间叶中未观察到POMC RNA的显著变化。这些研究表明，ADX后，成熟POMC mRNA的核转运的时间依赖性改变和/或POMC mRNA稳定性的变化，以及基因转录的变化可能解释了AL中表达的POMC mRNA的总体水平。我们已经举例说明了外显子/内含子探针用于精确定量稳定的说明核前体RNA的水平，其可以反映初级转录物的转录后加工中的转录应答和/或变化。
While the transcriptional effects of glucocorticoid hormone manipulation on the pituitary pro-opiomelanocortin (POMC) gene have been documented, it is not yet clear whether glucocorticoids activate additional post-transcriptional mechanisms to regulate POMC gene expression. We have used RNA probes that span exon/intron junctions in sensitive nuclease protection assays in order to examine changes in POMC precursor RNA as well as mature mRNA in nucleus and cytoplasm following both adrenalectomy (ADX) and administration of exogenous glucocorticoids. ADX led to a rapid and sustained 8- to 10-fold increase in the level of POMC primary transcript in the anterior lobe (AL), from 1 to 14 days after ADX. Stimulation of mature POMC mRNA in the nucleus was also rapid, with 7- to 8-fold increases evident by 1 day after ADX. In sharp contrast, the time-dependent accumulation of POMC mRNA in the cytoplasm was slow in comparison, reaching levels approximately 2-fold higher than sham-operated animals by 1 day post-ADX and 12-fold higher by 14 days after ADX. Despite the constant elevated level of nuclear POMC precursor RNA, the rate of accumulation of POMC mRNA in the corticotroph cytoplasm after ADX was not linear, with the greatest increase occurring within the first 1–4 days post-ADX. This led to alterations in the molar ratio of POMC primary transcript: nuclear mRNA: cytoplasmic mRNA in the AL at 1 and 4 days after ADX and showed a relative increase in the proportion of POMC RNA transcripts within the nucleus. Acute administration of dexamethasone to ADX rats resulted in rapid 80–90% inhibition of POMC primary transcript levels in the AL that was maximal by 30 min but with no associated change in mature mRNA. No significant changes in POMC RNA were seen in neurointermediate lobe in any of these studies. These studies suggest that following ADX, time-dependent alterations in nuclear transport of mature POMC mRNA and/or changes in POMC mRNA stability, in addition to changes in gene transcription may account for the overall level of POMC mRNA expressed in the AL. Furthermore, we have illustrated the use of exon/intron probes for accurately quantitating rapid alterations in steady-state levels of nuclear precursor RNA that may reflect transcriptional responses and/or changes in post-transcriptional processing of the primary transcript.