Kallunki T, Ikonen J, Chow L T, Kallunki P, Tryggvason K
Biocenter, University of Oulu, Finland.
J Biol Chem. 1991 Jan 5;266(1):221-8.
The exon-intron structure of the human laminin B2 chain gene was elucidated from genomic lambda phage clones spanning 2 kilobase pairs (kb) of the 5'-flanking region, 58 kb of the structural gene and 10 kb of the 3'-flanking region. The entire gene was shown to contain 28 exons. The promoter region has no TATA or CAAT boxes whereas it contains five GC boxes and three AP-2-like binding sites. Comparison with the promoter region of the mouse gene revealed six highly conserved sequences of 14 to 42 base pairs in length. Sequencing of the last exon of the gene showed that the 3'-untranslated region of the mRNA can be up to 2797 nucleotides with five AATAAA potential polyadenylation signals. The similarity of the human 3'-untranslated sequence with that of mouse was shown to be 68.8%. The exon-intron structure of the laminin B2 chain gene demonstrated extensive divergence from the human laminin B1 chain gene, which has 34 exons. Only three intron locations are conserved in these two genes. The overall exon profile of the laminin B2 chain gene correlates only marginally with the pattern of structural domains and internal cysteine-rich repeats in the laminin B2 polypeptide chain.
人层粘连蛋白B2链基因的外显子-内含子结构是通过跨越5'侧翼区2千碱基对（kb）、结构基因58 kb和3'侧翼区10 kb的基因组λ噬菌体克隆来阐明的。整个基因显示含有28个外显子。启动子区域没有TATA或CAAT框，但其含有五个GC框和三个AP-2样结合位点。与小鼠基因的启动子区域比较发现了六个长度为14至42个碱基对的高度保守序列。该基因最后一个外显子的测序表明，mRNA的3'非翻译区最长可达2797个核苷酸，带有五个AATAAA潜在聚腺苷酸化信号。人3'非翻译序列与小鼠的相似性为68.8%。层粘连蛋白B2链基因的外显子-内含子结构与具有34个外显子的人层粘连蛋白B1链基因有很大差异。这两个基因中只有三个内含子位置是保守的。层粘连蛋白B2链基因的整体外显子谱与层粘连蛋白B2多肽链中的结构域和内部富含半胱氨酸重复序列的模式仅存在微弱关联。
