Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT 06511, USA.
Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06511, USA; Institute for Biomolecular Design and Discovery, Yale University, West Haven, CT 06516, USA.
Cell Rep. 2022 Apr 19;39(3):110687. doi: 10.1016/j.celrep.2022.110687.
The p53-induced long noncoding RNA (lncRNA) lincRNA-p21 is proposed to act in cis to promote p53-dependent expression of the neighboring cell cycle gene, Cdkn1a/p21. The molecular mechanism through which the transcribed lincRNA-p21 regulatory locus activates p21 expression remains poorly understood. To elucidate the functional elements of cis-regulation, we generate a series of genetic models that disrupt DNA regulatory elements, the transcription of lincRNA-p21, or the accumulation of mature lincRNA-p21. Unexpectedly, we determine that full-length transcription, splicing, and accumulation of lincRNA-p21 are dispensable for the chromatin organization of the locus and for cis-regulation. Instead, we find that production of lincRNA-p21 through conserved regions in exon 1 of lincRNA-p21 promotes cis-activation. These findings demonstrate that the activation of nascent transcription from this lncRNA locus, but not the generation or accumulation of a mature lncRNA transcript, is necessary to enact local gene expression control.
p53 诱导的长非编码 RNA（lncRNA）lincRNA-p21 被提议在顺式作用中促进邻近细胞周期基因 Cdkn1a/p21 的 p53 依赖性表达。lncRNA-p21 转录调节基因座激活 p21 表达的分子机制仍知之甚少。为了阐明顺式调控的功能元件，我们生成了一系列遗传模型，这些模型破坏了 DNA 调节元件、lincRNA-p21 的转录或成熟 lincRNA-p21 的积累。出乎意料的是，我们确定全长转录、剪接和 lincRNA-p21 的积累对于基因座的染色质组织和顺式调控是可有可无的。相反，我们发现通过 lincRNA-p21 外显子 1 中的保守区域产生 lincRNA-p21 促进了顺式激活。这些发现表明，从这个 lncRNA 基因座产生新生转录，而不是生成或积累成熟的 lncRNA 转录本，对于实施局部基因表达控制是必要的。
