Fibulin-2 (FBLN2): human cDNA sequence, mRNA expression, and mapping of the gene on human and mouse chromosomes.
Fibulin-2 (FBLN2): human cDNA sequence, mRNA expression, and mapping of the gene on human and mouse chromosomes.
复制标题
Fibulin-2 (FBLN2)：人类 cDNA 序列、mRNA 表达以及该基因在人类和小鼠染色体上的定位。
作者：
Zhang,RZ;Pan,TC;Zhang,ZY;Mattei,MG;Timpl,R;Chu,ML
Fibulin-2是一种新的细胞外基质蛋白，是我们最近通过小鼠cDNA克隆鉴定出来的。fibuin -2 mRNA在小鼠心脏组织中显著表达，在其他组织中含量较低。在这项研究中，我们分离并测序了一个4.1 kb的人纤维蛋白-2 cDNA，该cDNA编码了一个由1157个氨基酸组成的成熟蛋白，其前面有一个27个残基的信号序列。预测的多肽在其中心区域包含三个连续的过敏毒素相关片段（结构域I），随后是10个egf样重复序列（结构域II），其中9个具有钙结合的一致序列。408个残基的n端区域由两个独立的子结构域组成，一个含有150个残基的富含半胱氨酸的片段（Na亚结构域）和一个含有一段酸性氨基酸的无半胱氨酸片段（Nb亚结构域）。115个残基的C端片段（结构域III）与纤维蛋白-1的C变体相似。人和小鼠纤维蛋白-2的氨基酸序列在Na、I、II和III结构域中有90%相同，但在Nb结构域中只有62%相同。人类cDNA缺乏egf样重复序列，该重复序列在小鼠cDNA克隆中可选择性剪接，并且在小鼠对应的Nb结构域中发现潜在的细胞结合Arg-Gly-Asp序列。Northern blot分析显示，来自不同人体组织的mRNA在心脏、胎盘和卵巢组织中有丰富的4.5 kb转录本。其表达模式与纤维蛋白-1不同。通过原位杂交将纤维蛋白-2基因定位在人3号染色体的p24-p25区和小鼠6号染色体的D-E带。
Fibulin-2 is a new extracellular matrix protein that we recently identified by characterizing mouse cDNA clones. Fibulin-2 mRNA is prominently expressed in mouse heart tissue and is present in low amounts in other tissues. In this study, we isolated and sequenced a 4.1-kb human fibulin-2 cDNA, which encoded a mature protein of 1157 amino acids preceded by a 27-residue signal sequence. The predicted polypeptide contains three consecutive anaphylatoxin-related segments (domain I) in its central region followed by 10 EGF-like repeats (domain II), 9 of which have a consensus sequence for calcium binding. The 408-residue N-terminal region consists of two separate subdomains, a cysteine-rich segment of 150 residues (Na subdomain) and a cysteine-free segment with a stretch of acidic amino acids (Nb subdomain). The 115-residue C-terminal segment (domain III) is similar to the C variant of fibulin-1. The amino acid sequences of the human and mouse fibulin-2 share ∼90% identity in domains Na, I, II, and III but only 62% identity in domain Nb. The human cDNA lacks an EGF-like repeat, which is alternatively spliced in the mouse cDNA clones, and a potential cell-binding Arg-Gly-Asp sequence found in the Nb domain of the mouse counterpart. Northern blot analysis of mRNA from various human tissues reveals an abundant 4.5-kb transcript in heart, placenta, and ovary tissue. The expression pattern differs from that of fibulin-1. The fibulin-2 gene was localized byin situhybridization to the p24-p25 region of human chromosome 3 and to the band D-E of mouse chromosome 6.