Department of Biochemistry and Molecular Biology, Penn State University, University Park, Pennsylvania, United States of America.
Cancer Biology and Genetics Program, Memorial Sloan Kettering Cancer Center, New York, New York, United States of America.
PLoS One. 2023 Dec 27;18(12):e0296176. doi: 10.1371/journal.pone.0296176. eCollection 2023.
Forkhead box E1 (FoxE1) protein is a transcriptional regulator known to play a major role in the development of the thyroid gland. By performing sequence alignments, we detected a deletion in FoxE1, which occurred in the evolution of mammals, near the point of divergence of placental mammals. This deletion led to the loss of the majority of the Eh1 motif, which was important for interactions with transcriptional corepressors. To investigate a potential mechanism for this deletion, we analyzed replication through the deletion area in mammalian cells with two-dimensional gel electrophoresis, and in vitro, using a primer extension reaction. We demonstrated that the area of the deletion presented an obstacle for replication in both assays. The exact position of polymerization arrest in primer extension indicated that it was most likely caused by a quadruplex DNA structure. The quadruplex structure hypothesis is also consistent with the exact borders of the deletion. The exact roles of these evolutionary changes in FoxE1 family proteins are still to be determined.
叉头框 E1（FoxE1）蛋白是一种转录调节因子，已知在甲状腺发育中发挥主要作用。通过进行序列比对，我们在哺乳动物的进化过程中，在胎盘哺乳动物分化点附近检测到 FoxE1 的缺失。该缺失导致 Eh1 基序的大部分丢失，而 Eh1 基序对于与转录共抑制因子的相互作用很重要。为了研究这种缺失的潜在机制，我们使用二维凝胶电泳分析了哺乳动物细胞中通过缺失区域的复制，并且在体外使用引物延伸反应进行了分析。我们证明，缺失区域在这两种检测方法中都呈现出复制的障碍。引物延伸中聚合酶停滞的确切位置表明，它很可能是由四链体 DNA 结构引起的。四链体结构假说也与缺失的精确边界一致。这些在 FoxE1 家族蛋白中的进化变化的确切作用仍有待确定。
