Cloning, characterization and developmental regulation of two members of a novel human gene family of neurite outgrowth-promoting proteins.
Cloning, characterization and developmental regulation of two members of a novel human gene family of neurite outgrowth-promoting proteins.
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DOI：
10.3109/08977199109000275
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发表时间：
1991-01-01
期刊：
影响因子：
--
通讯作者：
Kovesdi, I
中科院分区：
文献类型：
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作者：
Kretschmer, P J;Fairhurst, J L;Kovesdi, I
本报告描述了一个新的人类蛋白基因家族的两个成员的克隆、表达和特性，这两个蛋白HBNF和MK具有促进轴突生长的活性。HBNF基因编码一个168个残基的蛋白质，是先前描述的由136个氨基酸组成的脑源性肝素结合蛋白的前体。这项研究中发现的第二个人类基因，称为MK，编码一个143个残基的蛋白质(包括一个22个氨基酸的信号序列)，与HBNF有46%的同源性。编码HBNF和MK成熟蛋白的互补DNA在细菌中表达，肝素亲和层析纯化。这些重组蛋白具有促进轴突生长的活性，但缺乏有丝分裂活性。HBNF基因在成年小鼠和大鼠的大脑中都有表达，但在这个组织中只有少量的MK表达。在胚胎发育过程中观察到不同的表达模式，其中MK在E12~E14天在脑中的表达达到高峰，在成体中下降到最低水平，而HBNF mRNA的表达在胚胎发育过程中逐渐增加，出生时达到最高水平，并一直维持到成年。在人胚胎癌细胞株NT2/D1中也观察到了这些基因的表达。维甲酸诱导HBNF和MK的表达分别为该细胞株的6倍和11倍。我们的研究表明，HBNF和MK是一个高度保守的、发育调节的新基因家族的成员，这些基因可能在神经组织的发育和/或维持中发挥作用。
This report describes the cloning, expression and characterization of two members of a novel human gene family of proteins, HBNF and MK, which exhibit neurite outgrowth-promoting activity. The HBNF cDNA gene codes for a 168-residue protein which is a precursor for a previously described brain-derived heparin-binding protein of 136 amino acids. The second human gene identified in this study, called MK, codes for a 143-residue protein (including a 22-amino acid signal sequence) which is 46% homologous with HBNF. Complementary DNA constructs coding for the mature HBNF and MK proteins were expressed in bacteria and purified by heparin affinity chromatography. These recombinant proteins exhibited neurite-outgrowth promoting activity, but lacked mitogenic activity. The HBNF gene is expressed in the brain of adult mice and rats, but only minimal expression of MK was observed in this tissue. Different patterns of developmental expression were observed in the embryonic mouse, with MK expression peaking in the brain between days E12 and E14 and diminishing to minimal levels in the adult, while expression of HBNF mRNA was observed to gradually increase during embryogenesis, reaching a maximal level at birth and maintaining this level into adulthood. Expression of these genes was also observed in the human embryonal carcinoma cell line, NT2/D1. Retinoic acid induced the expression of HBNF and MK 6- and 11-fold, respectively, in this cell line. Our studies indicate that HBNF and MK are members of a new family of highly conserved, developmentally regulated genes that may play a role in nervous tissue development and/or maintenance.