BHLHE41基因
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BHLHE41基因(亦称DEC2、hDEC2、SHARP1,曾用名为BHLHB3[1])是一个编码一种碱性螺旋‑环‑螺旋转录因子抑制蛋白的基因,在人类和小鼠的多种组织中均有表达[2][3][4]。该基因在昼夜节律的分子机制中发挥了关键作用,其参与调节睡眠时长;同时也涉及免疫功能,尤其与体液免疫相关的2型辅助性T细胞谱系成长过程密切相关[5][6]。
蛋白结构[编辑]
BHLHE41属于碱性螺旋‑环‑螺旋蛋白家族中的DEC亚族[7][8]。该基因定位于人类12号染色体(反向链,26,120,026–26,125,127),全长为5,101个碱基对[9];在小鼠和大鼠中分别定位于6号染色体的G2-G3区与4号染色体的q43远端‑q4区[7]。该基因存在3种已知剪接变体:BHLHE41-002和BHLHE41-003为内含子保留形式,不编码成蛋白;BHLHE41-001包含5个编码外显子,转录本长3,837个碱基对,编码由482个氨基酸组成的BHLHE41蛋白[10]。其旁系同源基因为BHLHE40[11],目前已知的直系同源基因有165个[12]。
BHLHE41蛋白具有一个myc型的碱性螺旋‑环‑螺旋结构域及一个orange结构域[10]。orange结构域是位于碱性螺旋‑环‑螺旋结构域羧基末端的一段约30个残碱基序列,功能尚不明确[13]。碱性螺旋‑环‑螺旋结构域介导蛋白二聚化,并通过结合特定DNA序列来调控基因转录[14]。该蛋白的羧基末端富含丙氨酸和甘氨酸,且缺乏与共抑制子Groucho相互作用的WRPW基序[7]。
在分子机制上,BHLHE41通过招募组蛋白甲基转移酶G9a以及组蛋白去乙酰化酶HDAC1与Sirt1,以介导染色质的修饰,从而抑制靶基因的表达[15]。
功能[编辑]
昼夜节律功能[编辑]
BHLHE41在视交叉上核中呈节律性表达,其水平在白天达到峰值[16]。该基因编码的蛋白属于Hes亚族转录抑制因子,能够通过竞争性抑制来调节生物钟[17]:
BHLHE41既是转录抑制因子,也是昼夜节律的调节因子[4]:在昼夜节律中,转录因子时针遗传子(CLOCK)和碱性螺旋-环-螺旋ARNTL(BMAL1)的蛋白二聚体结合E‑box启动元件,以激活Per等时钟基因开始转录[18];BHLHE41蛋白随后进入细胞核,与CLOCK‑BMAL1竞争结合E‑box,从而抑制Per基因的转录,形成负反馈环路[16]。
非节律功能[编辑]
BHLHE41亦涉及其它多条信号通路:其转录水平失调与多种肿瘤进展相关,在低表达水平时常伴随有肿瘤生长,提示其可能具有抑制肿瘤增殖的作用,但具体的机制尚未明确[19]。根据初步研究显示,BHLHE41蛋白可能参与免疫应答的调控[20]。这些非节律功能的具体分子通路及其生物学意义,仍有待进一步研究。
在小鼠模型中,缺失SHARP1/BHLHE41与SHARP2会导致IGF‑2水平升高,进而增强记忆巩固能力[21]。
基因突变[编辑]
DEC2-P385R点突变[编辑]
在某个表现为家族性自然短睡眠的家族中发现了一种突变(DNA序列中C替换为G),导致BHLHE41蛋白第384位的脯氨酸被精氨酸取代。该突变位于BHLHE41蛋白羧基末端富含脯氨酸的结构域内,靠近与组蛋白去乙酰化酶相互作用的区域,这一区域在进化中高度保守[14]。实验表明,此突变会削弱BHLHE41的转录抑制功能[22]。
但后续基于大规模生物样本的研究显示,携带该突变或BHLHE41其他明显突变的部分个体并未出现睡眠时长的改变,提示该家族的短睡眠表型可能另有原因[23]。
BHLHE41基因敲除[编辑]
在BHLHE41被敲除的小鼠中,其活动节律的周期未发生改变。但在特定的病理模型中观察到以下表型:在过敏性哮喘的模型中,被敲除基因的小鼠表现出TH2细胞因子产生减少、进行反复卵清蛋白刺激后TH2的应答缺陷以及肺泡浸润减轻[5]。其出生后肌肉损伤后的再生能力提高,但胚胎期的肌肉修复未受影响[24]。
临床意义[编辑]
免疫调节[编辑]
BHLHE41是T细胞激活的关键调节因子,通过Stat6依赖性机制上调CD25的表达,进而增强IL‑2受体介导的信号通路,促进TH2细胞的分化。GATA3通过自身调节环路来调控BHLHE41表达,进一步加促进TH2的分化[15]。
低氧[编辑]
在低氧条件下,缺氧诱导因子HIF-1α诱导BHLHE41与BHLHE40的转录,这被认为可以抑制细胞增殖,但这并不利于低氧环境[25]。此外,BHLHE41还能将HIF‑1α导向蛋白酶体的复合物,促进其降解,从而阻断低氧反应[15]。
肌肉发育与代谢[编辑]
BHLHE41通过多种机制抑制肌肉生成:与MyoD及E47形成异源二聚体,以阻碍功能性MyoD‑E47蛋白二聚体形成;其SUMO化修饰(K240/K255点位)可募集组蛋白甲基转移酶G9a,催化MyoD的靶基因启动H3K9me2的抑制性修饰,同时G9a还可甲基化MyoD本身以抑制其转录活性[15]。BHLHE41和BHLHE41能改变骨骼肌中多种收缩蛋白和线粒体蛋白的表达,它们还受SREBP‑1的亚型诱导表达,进而抑制MYOD1转录,这在肌肉中形成了以24小时为周期的负反馈环路[25]。此外,BHLHE41还能抑制肌肉炎症和脂肪生成[26]。
肉瘤、口腔癌、肝癌与结肠癌[编辑]
BHLHE41在肉瘤和口腔癌的细胞中能抑制VEGF的表达,在肝细胞癌中能抑制CYP2D6。与BHLHE40促进肿瘤细胞凋亡、衰老和上皮间质转化不同,BHLHE41呈现昼夜节律性表达,并在肉瘤和肝细胞癌中抑制上皮间质转化、凋亡和转移[26]。在结肠癌旁的正常组织中BHLHE41呈现高表达[27],目前研究正在探索其作为化疗靶点的潜力。
乳腺癌[编辑]
BHLHE41是三阴性乳腺癌转移的关键抑制因子,受p63转移抑制蛋白调控,通过抑制HIF‑1α和HIF‑2α发挥作用。它通过与缺氧诱导因子结合并促进其蛋白酶体降解,可以有效限制缺氧诱导因子靶基因的表达[28]。BHLHE41与CyclinG2高表达的乳腺癌转移风险较低[29][30]。
历史[编辑]
BHLHE41和BHLHE40最初由Klaus-Armin Nave实验室鉴定为碱性螺旋-环-螺旋蛋白家族的一个新亚族。该亚族的特征是其编码基因在胚胎发育的末期才开始转录,从而与其他碱性螺旋-环-螺旋蛋白的基因区分开来[31]。
BHLHE41 的DNA序列最早由Yukia Kato实验室通过cDNA文库筛选获得。该团队在获得BHLHE40序列的基础上,通过表达序列标签搜索确定了 BHLHE41的序列。两者在BHLH结构域具有97%的同源性[7]。
随后,Ken-Ichi Honma实验室揭示了BHLHE41在哺乳动物生物钟调控中的关键作用。目前,该基因在其他通路中的功能仍在进一步探索中[16]。
参考资料[编辑]
- ↑ GeneCards Human Gene Database. BHLHE41 Gene - GeneCards | BHE41 Protein | BHE41 Antibody. www.genecards.org. [2025-12-21]. (原始内容存档于2014-05-28).
- ↑ BHLHE41 basic helix-loop-helix family member e41 [Homo sapiens (human)] - Gene - NCBI. www.ncbi.nlm.nih.gov. [2025-12-21].
- ↑ Stevens, Jeffrey D.; Roalson, Eric H.; Skinner, Michael K. Phylogenetic and expression analysis of the basic helix-loop-helix transcription factor gene family: genomic approach to cellular differentiation. Differentiation. 2008-11-01, 76 (9) [2025-12-21]. ISSN 0301-4681. PMC 5728086 可免费查阅. PMID 18557763. doi:10.1111/j.1432-0436.2008.00285.x.
- ↑ 4.0 4.1 BHLHE41 basic helix-loop-helix family member e41 [Homo sapiens (human)] - Gene - NCBI. www.ncbi.nlm.nih.gov. [2025-12-21].
- ↑ 5.0 5.1 Kurien, Philip A; Chong, SY Christin; Ptáček, Louis J; Fu, Ying-Hui. Sick and tired: how molecular regulators of human sleep schedules and duration impact immune function. Current Opinion in Neurobiology. Circadian rhythm and sleep. 2013-10-01, 23 (5) [2025-12-21]. ISSN 0959-4388. PMC 3766463 可免费查阅. PMID 23702243. doi:10.1016/j.conb.2013.04.014.
- ↑ Yang, Xuexian O.; Angkasekwinai, Pornpimon; Zhu, Jinfang; Peng, Juan; Liu, Zhiduo; Nurieva, Roza; Liu, Xikui; Chung, Yeonseok; Chang, Seon Hee; Sun, Bing; Dong, Chen. Requirement for the basic helix-loop-helix transcription factor Dec2 in initial TH2 lineage commitment. Nature Immunology. 2009-12, 10 (12) [2025-12-21]. ISSN 1529-2916. PMC 2784129 可免费查阅. PMID 19881507. doi:10.1038/ni.1821 (English).
- ↑ 7.0 7.1 7.2 7.3 Fujimoto, Katsumi; Shen, Ming; Noshiro, Mitsuhide; Matsubara, Kazumi; Shingu, Sohei; Honda, Kiyomasa; Yoshida, Eri; Suardita, Ketut; Matsuda, Yoichi; Kato, Yukio. Molecular Cloning and Characterization of DEC2, a New Member of Basic Helix-Loop-Helix Proteins. Biochemical and Biophysical Research Communications. 2001-01-12, 280 (1) [2025-12-21]. ISSN 0006-291X. doi:10.1006/bbrc.2000.4133.
- ↑ BHLHE41 Symbol Report | HUGO Gene Nomenclature Committee. www.genenames.org. [2025-12-21]. (原始内容存档于2017-04-13).
- ↑ Gene: BHLHE41 (ENSG00000123095) - Summary - Homo_sapiens - Ensembl genome browser 115. www.ensembl.org. [2025-12-21].
- ↑ 10.0 10.1 Transcript: ENST00000541271.1 (BHLHE41-203) - Summary - Homo_sapiens - Ensembl genome browser 115. www.ensembl.org. [2025-12-21].
- ↑ Gene: BHLHE41 (ENSG00000123095) - Paralogues - Homo_sapiens - Ensembl genome browser 115. www.ensembl.org. [2025-12-21].
- ↑ ortholog_gene_79365[group] - Gene - NCBI. www.ncbi.nlm.nih.gov. [2025-12-21].
- ↑ Jones, Susan. An overview of the basic helix-loop-helix proteins. Genome Biology. 2004-05-28, 5 (6) [2025-12-21]. ISSN 1474-760X. PMC 463060 可免费查阅. PMID 15186484. doi:10.1186/gb-2004-5-6-226 (English).
- ↑ 14.0 14.1 He, Ying; Jones, Christopher R.; Fujiki, Nobuhiro; Xu, Ying; Guo, Bin; Holder, Jimmy L.; Rossner, Moritz J.; Nishino, Seiji; Fu, Ying-Hui. The Transcriptional Repressor DEC2 Regulates Sleep Length in Mammals. Science. 2009-08-14, 325 (5942) [2025-12-21]. PMC 2884988 可免费查阅. PMID 19679812. doi:10.1126/science.1174443.
- ↑ 15.0 15.1 15.2 15.3 Stra13 and Sharp-1, the Non-Grouchy Regulators of Development and Disease 110, Academic Press: 317–338, 2014-01-01 [2025-12-21], doi:10.1016/B978-0-12-405943-6.00009-9 (en-US)
- ↑ 16.0 16.1 16.2 Honma, Sato; Kawamoto, Takeshi; Takagi, Yumiko; Fujimoto, Katsumi; Sato, Fuyuki; Noshiro, Mitsuhide; Kato, Yukio; Honma, Ken-ichi. Dec1 and Dec2 are regulators of the mammalian molecular clock. Nature. 2002-10, 419 (6909) [2025-12-21]. ISSN 1476-4687. doi:10.1038/nature01123 (English).
- ↑ Piscione, Tino D.; Wu, Megan Y. J.; Quaggin, Susan E. Expression of Hairy/Enhancer of Split genes, Hes1 and Hes5, during murine nephron morphogenesis. Gene Expression Patterns. 2004-10-01, 4 (6) [2025-12-21]. ISSN 1567-133X. doi:10.1016/j.modgep.2004.04.007.
- ↑ DEC1/STRA13/SHARP2 and DEC2/SHARP1 Coordinate Physiological Processes, Including Circadian Rhythms in Response to Environmental Stimuli 110, Academic Press: 339–372, 2014-01-01 [2025-12-21], doi:10.1016/B978-0-12-405943-6.00010-5 (en-US)
- ↑ Li, Ping; Jia, Yan-Fei; Ma, Xiao-Li; Zheng, Yan; Kong, Yi; Zhang, Yao; Zong, Shuai; Chen, Zhi-Tao; Wang, Yun-Shan. DEC2 suppresses tumor proliferation and metastasis by regulating ERK/NF-κB pathway in gastric cancer. American Journal of Cancer Research. 2016, 6 (8) [2025-12-21]. ISSN 2156-6976. PMC 5004076 可免费查阅. PMID 27648362.
- ↑ Kurien, Philip A.; Chong, S. Y. Christin; Ptáček, Louis J.; Fu, Ying-Hui. Sick and tired: how molecular regulators of human sleep schedules and duration impact immune function. Current Opinion in Neurobiology. 2013-10, 23 (5) [2025-12-21]. ISSN 1873-6882. PMC 3766463 可免费查阅. PMID 23702243. doi:10.1016/j.conb.2013.04.014.
- ↑ Shahmoradi, Ali; Radyushkin, Konstantin; Rossner, Moritz J. Enhanced memory consolidation in mice lacking the circadian modulators Sharp1 and -2 caused by elevated Igf2 signaling in the cortex. Proceedings of the National Academy of Sciences. 2015-07-07, 112 (27) [2025-12-21]. PMC 4500222 可免费查阅. PMID 26100875. doi:10.1073/pnas.1423989112.
- ↑ Jones, Christopher R.; Huang, Angela L.; Ptáček, Louis J.; Fu, Ying-Hui. Genetic basis of human circadian rhythm disorders. Experimental Neurology. Circadian rhythms and sleep disorders. 2013-05-01, 243 [2025-12-21]. ISSN 0014-4886. PMC 3514403 可免费查阅. PMID 22849821. doi:10.1016/j.expneurol.2012.07.012.
- ↑ Weedon, Michael N.; Jones, Samuel E.; Lane, Jacqueline M.; Lee, Jiwon; Ollila, Hanna M.; Dawes, Amy; Tyrrell, Jess; Beaumont, Robin N.; Partonen, Timo; Merikanto, Ilona; Rich, Stephen S. The impact of Mendelian sleep and circadian genetic variants in a population setting. PLoS genetics. 2022-09, 18 (9) [2025-12-21]. ISSN 1553-7404. PMC 9499244 可免费查阅. PMID 36137075. doi:10.1371/journal.pgen.1010356.
- ↑ Gorski, Jeffrey P; Price, Jeffrey L. Bone muscle crosstalk targets muscle regeneration pathway regulated by core circadian transcriptional repressors DEC1 and DEC2. BoneKEy Reports. 2016-11-16, 5 [2025-12-21]. PMC 5111231 可免费查阅. PMID 27867498. doi:10.1038/bonekey.2016.80.
- ↑ 25.0 25.1 Gorski, Jeffrey P; Price, Jeffrey L. Bone muscle crosstalk targets muscle regeneration pathway regulated by core circadian transcriptional repressors DEC1 and DEC2. BoneKEy Reports. 2016-11-16, 5 [2025-12-21]. PMC 5111231 可免费查阅. PMID 27867498. doi:10.1038/bonekey.2016.80.
- ↑ 26.0 26.1 Sato, Fuyuki; Bhawal, Ujjal K.; Yoshimura, Tomohiro; Muragaki, Yasuteru. DEC1 and DEC2 Crosstalk between Circadian Rhythm and Tumor Progression. Journal of Cancer. 2016, 7 (2) [2025-12-21]. ISSN 1837-9664. PMC 4716847 可免费查阅. PMID 26819638. doi:10.7150/jca.13748.
- ↑ Yamada, Kazuya; Miyamoto, Kaoru. Basic helix-loop-helix transcription factors, BHLHB2 and BHLHB3; their gene expressions are regulated by multiple extracellular stimuli. Frontiers in Bioscience-Landmark. 2005-09-01, 10 (3) [2025-12-21]. ISSN 2768-6698. doi:10.2741/1772 (English).
- ↑ Montagner, Marco; Enzo, Elena; Forcato, Mattia; Zanconato, Francesca; Parenti, Anna; Rampazzo, Elena; Basso, Giuseppe; Leo, Genesio; Rosato, Antonio; Bicciato, Silvio; Cordenonsi, Michelangelo. SHARP1 suppresses breast cancer metastasis by promoting degradation of hypoxia-inducible factors. Nature. 2012-07-19, 487 (7407) [2025-12-21]. ISSN 1476-4687. PMID 22801492. doi:10.1038/nature11207.
- ↑ Noshiro, Mitsuhide; Kawamoto, Takeshi; Furukawa, Masae; Fujimoto, Katsumi; Yoshida, Yuzo; Sasabe, Eri; Tsutsumi, Shinichi; Hamada, Taizo; Honma, Sato; Honma, Ken-ichi; Kato, Yukio. Rhythmic expression of DEC1 and DEC2 in peripheral tissues: DEC2 is a potent suppressor for hepatic cytochrome P450s opposing DBP. Genes to Cells. 2004, 9 (4) [2025-12-21]. ISSN 1365-2443. doi:10.1111/j.1356-9597.2004.00722.x (English).
- ↑ Piccolo, Stefano; Enzo, Elena; Montagner, Marco. p63, Sharp1, and HIFs: Master Regulators of Metastasis in Triple-Negative Breast Cancer. Cancer Research. 2013-08-15, 73 (16) [2025-12-21]. ISSN 0008-5472. doi:10.1158/0008-5472.CAN-13-0962 (English).
- ↑ Rossner, M. J.; Dörr, J.; Gass, P.; Schwab, M. H.; Nave, K. A. SHARPs: mammalian enhancer-of-split- and hairy-related proteins coupled to neuronal stimulation. Molecular and Cellular Neurosciences. 1997, 9 (5-6) [2025-12-21]. ISSN 1044-7431. PMID 9361282. doi:10.1006/mcne.1997.0640.
外部链接[编辑]
- BHLHE41:UCSC基因组浏览器的BHLHE41基因