Presence of a long nuclear-localization signal sequence in homeodomain transcription factor Nkx 1.2  

作　　者：Xinyi LI Lihui CHEN Xinyuan WANG Chen SUN Guangdong JI Guobin HU Zhenhui LIU 

机构地区：[1]College of Marine Life Science and Institute of Evolution&Marine Biodiversity,Ocean University of China,Qingdao 266003,China [2]Laoshan Laboratory,Qingdao 266237,China

出　　处：《Journal of Oceanology and Limnology》2024年第2期620-626,共7页海洋湖沼学报（英文）

基　　金：Supported by the National Natural Science Foundation of China(No.31970429);the Shandong Provincial Natural Science Foundation(No.ZR 2022 MC 032)。

摘　　要：Homeodomains,a 60-amino acid sequence encoded by 180 nucleotides,are highly conserved DNA-binding motifs that are present in a variety of transcription factors in species ranging from yeast to humans.The NKX proteins belong to the homeodomain(HD)-containing transcription factor family.They play vital roles in the regulation of morphogenesis.NKX1-2 is one member of the NKX subfamily.At present,information about its nuclear localization signal(NLS)sequence is limited.We studied the NLS sequence of zebrafish Nkx1.2 by introducing sequence changes such as deletion,mutation,and truncation,and identified an NLS motif(QNRRTKWKKQ)that is localized at the C-terminus of the homeodomain.Moreover,the deletion of two amino acid residues(RR)in this NLS motif prevents Nkx1.2 from entering the nucleus,indicating that the two amino acids are essential for Nkx1.2 nuclear localization.However,the NLS motif alone is unable to target cytoplasmic protein glutathione S-transferase(GST)to the nucleus.An intact homeodomain is necessary for mediating the complete nuclear transport of cytoplasmic protein.Unlike most nuclear import proteins with short NLS sequences,a long NLS is present in zebrafish Nkx1.2.We also demonstrated that the sequences of homeodomain of NKX1.2 are well conserved among different species.This study is informative to verify the function of the NKX1.2 protein.

关 键 词：NKX1.2 NKX protein HOMEODOMAIN nuclear localization signal(NLS) nuclear transport 

分 类 号：Q75[生物学—分子生物学]