西北农林科技大学刘军团队的一项最新研究显示，hfCas12Max介导的山羊源UCOE在可接近染色质区域的靶向整合增强了稳定的重组乳铁蛋白表达。2025年11月17日，国际知名学术期刊《遗传学报》发表了这一成果。

为了解决这个问题，研究小组分析了山羊乳腺上皮细胞（GMECs）中ATAC-seq主题的染色质可及性，并确定了15个高度可及的基因组区域。其中三个区域被证实支持稳定的转基因表达。值得注意的是，研究人员在SF3B1-COQ10B基因间区发现了山羊衍生的泛素染色质开放元件（UCOE），具有高GC含量（65%）和CpG岛富集。这种UCOE改善了hfCas12Max介导的大片段DNA整合，并维持了人乳铁蛋白（hLTF）在GMECs中的高水平表达。

随后，该研究组将UCOE-hLTF盒精确整合到高度可接近的基因座中，并通过体细胞核移植产生转基因山羊，没有可检测到的脱靶效应。他们的研究整合了染色质可及性分析、UCOE发现和精确编辑，证明了含有CpG岛的UCOE在防止转基因沉默中的作用。该研究为提高重组蛋白产量提供了有价值的工具，为奶山羊的高乳铁蛋白含量提供了支持，同时促进了对分子育种中染色质、调控元件和转基因之间相互作用的理解。

研究人员表示，奶牛乳腺中稳定的转基因表达对重组蛋白的生产至关重要，但它经常受到转基因沉默和随机整合的阻碍。

附：英文原文

Title: hfCas12Max-mediated targeted integration at accessible chromatin regions with a goat-derived UCOE enhances stable recombinant lactoferrin expression

Author: Yong Zhang a b c, Yuanpeng Gao a b, Jun Liu a b c

Issue&Volume: 2025/11/17

Abstract: Stable transgene expression in the mammary gland is crucial for recombinant protein production in livestock, yet it is frequently hampered by transgene silencing and random integration. To address this, we profile chromatin accessibility in goat mammary epithelial cells (GMECs) using ATAC-seq and identify 15 highly accessible genomic regions. Three of these regions are confirmed to support stable transgene expression. Notably, we identify a goat-derived ubiquitous chromatin opening element (UCOE) in the SF3B1-COQ10B intergenic region, with a high GC content (65%) and CpG island enrichment. This UCOE improves hfCas12Max-mediated integration of large DNA fragments and maintains high-level expression of human lactoferrin (hLTF) in GMECs. Subsequently, we precisely integrate the UCOE-hLTF cassette into the highly accessible loci and generate a transgenic goat via somatic cell nuclear transfer, without detectable off-target effects. Our pipeline, which integrates chromatin accessibility profiling, UCOE discovery, and precision editing, demonstrates the role of CpG island-containing UCOEs in preventing transgene silencing. The study provides valuable tools for enhancing recombinant protein production and supports the breeding of dairy goats for milk with high lactoferrin content, while advancing the understanding of the interactions between chromatin, regulatory elements, and transgenes in molecular breeding.

DOI: 10.1016/j.jgg.2025.11.008

Source: https://www.sciencedirect.com/science/article/abs/pii/S167385272500298X