Shamnas V Muhammed, Singh Akanksha, Kumar Anuj, Mishra Gyan Prakash, Sinha Subodh Kumar
ICAR-National Institute for Plant Biotechnology, Pusa Campus, New Delhi 110012, India.
Department of Botany and Plant Pathology, Lilly Hall of Life Sciences, Purdue University, West Lafayette 47906, Indiana, USA.
AoB Plants. 2024 Mar 20;16(2):plae014. doi: 10.1093/aobpla/plae014. eCollection 2024 Feb.
Exitrons are exonic introns. This subclass of intron retention alternative splicing does not contain a Pre-Terminating stop Codon. Therefore, when retained, they are always a part of a protein. Intron retention is a frequent phenomenon predominantly found in plants, which results in either the degradation of the transcripts or can serve as a stable intermediate to be processed upon induction by specific signals or the cell status. Interestingly, exitrons have coding ability and may confer additional attributes to the proteins that retain them. Therefore, exitron-containing and exitron-spliced isoforms will be a driving force for creating protein diversity in the proteome of an organism. This review establishes a basic understanding of exitron, discussing its genesis, key features, identification methods and functions. We also try to depict its other potential roles. The present review also aims to provide a fundamental background to those who found such exitronic sequences in their gene(s) and to speculate the future course of studies.
外显子内元是外显子中的内含子。这种内含子保留可变剪接的亚类不包含提前终止密码子。因此，当被保留时，它们始终是蛋白质的一部分。内含子保留是一种常见现象，主要存在于植物中，其结果要么是转录本的降解，要么可以作为一种稳定的中间体，在特定信号或细胞状态的诱导下进行加工。有趣的是，外显子内元具有编码能力，可能会赋予保留它们的蛋白质额外的特性。因此，含外显子内元和经外显子内元剪接的异构体将成为生物体蛋白质组中产生蛋白质多样性的驱动力。本综述建立了对外显子内元的基本理解，讨论了其起源、关键特征、鉴定方法和功能。我们还试图描述其其他潜在作用。本综述还旨在为那些在其基因中发现此类外显子内元序列的人提供基本背景，并推测未来的研究方向。
