Department of Chemistry, The Scripps Research Institute, La Jolla, CA 92037.
Department of Chemistry, Pusan National University, Busan 46241, Republic of Korea.
Proc Natl Acad Sci U S A. 2021 Jan 26;118(4). doi: 10.1073/pnas.2021943118.
Recent technological advances have expanded the annotated protein coding content of mammalian genomes, as hundreds of previously unidentified, short open reading frame (ORF)-encoded peptides (SEPs) have now been found to be translated. Although several studies have identified important physiological roles for this emerging protein class, a general method to define their interactomes is lacking. Here, we demonstrate that genetic incorporation of the photo-crosslinking noncanonical amino acid AbK into SEP transgenes allows for the facile identification of SEP cellular interaction partners using affinity-based methods. From a survey of seven SEPs, we report the discovery of short ORF-encoded histone binding protein (SEHBP), a conserved microprotein that interacts with chromatin-associated proteins, localizes to discrete genomic loci, and induces a robust transcriptional program when overexpressed in human cells. This work affords a straightforward method to help define the physiological roles of SEPs and demonstrates its utility by identifying SEHBP as a short ORF-encoded transcription factor.
最近的技术进步扩大了哺乳动物基因组中注释的蛋白编码内容，因为现在已经发现了数百个以前未被识别的短开放阅读框（ORF）编码肽（SEP）被翻译。尽管有几项研究已经确定了这个新兴蛋白类别的重要生理作用，但缺乏一种通用的方法来定义它们的互作组。在这里，我们证明了将光交联非典型氨基酸 AbK 遗传掺入 SEP 转基因中，可以使用基于亲和性的方法轻松鉴定 SEP 的细胞相互作用伙伴。通过对七个 SEP 的调查，我们报告了短 ORF 编码组蛋白结合蛋白（SEHBP）的发现，SEHBP 是一种保守的微蛋白，与染色质相关蛋白相互作用，定位于离散的基因组位置，并在人细胞中转录过度表达时诱导强大的转录程序。这项工作提供了一种简单的方法来帮助定义 SEP 的生理作用，并通过将 SEHBP 鉴定为短 ORF 编码的转录因子来证明其效用。
