人类β 7亚基的基因组织，白细胞整合素HML-1和LPAM-1的常见β亚基。
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蒋文敏，詹金斯D，袁Q，梁娥，周克杰，Watson JD, Krissansen GW
人类β 7亚基的基因组织，白细胞整合素HML-1和LPAM-1的常见β亚基。
国际免疫杂志1992 9月4(9):1031-40。
- PubMed ID
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1382574 (PubMed视图］
- 摘要
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整合素7亚基与两个可选的α亚基结合，称为α HML-1和α 4，使淋巴细胞活化和归巢受体HML-1和LPAM-1。编码人类β 7亚基基因的重叠基因组克隆从cosmid和噬菌体lambda文库中分离出来。该基因的编码部分约10 kb，由14个外显子组成。外显子1 (123 bp)编码5'未翻译序列;外显子2 (204 bp)编码成熟蛋白n端起始密码子、信号肽和50个氨基酸残基;7个外显子(3-9外显子)，大小90 bp - 242 bp，编码了4个富半胱氨酸重复序列近端的大部分胞外结构域;- 3精氨酸-甘氨酸-天冬氨酸(RGD)结合域对应的区域在外显子4和5之间被划分;4个富半胱氨酸重复序列由3个外显子编码(外显子10-12)，内含子插入到第1和第3个重复序列;外显子13 (209 bp)在富半胱氨酸结构域和跨膜结构域之间提供了一个间隔;外显子14 (161 bp)编码跨膜域和恰好一半的细胞质域; the remainder of the cytoplasmic domain and most of the 3' untranslated region was contained in the largest 313 bp exon 15. Comparison of integrin beta subunit genes revealed that the gene organization of beta 7 was almost identical to that of beta 2, but had diverged from that of beta 3. Amplification of integrin DNAs directly from genomic DNA, using PCR primers based on beta subunit consensus sequences corresponding to the beta 3 RGD-binding domain, yielded partial gene sequences for the beta 3, beta 5, and beta 6 subunits only. Inspection of the amplified sequences revealed that, as for beta 3, the regions in beta 5 and beta 6 corresponding to the beta 3 RGD-binding domain lacked the intron present in beta 7, beta 1, and beta 2, which divides this region in beta 2 into two subdomains that contribute to subunit assembly. This study provides genetic evidence for at least two major branches to the integrin beta subunit evolutionary tree, with beta 7, beta 2, and probably beta 1 in one branch, and the cytoadhesin beta 3 and probably also beta 5 and beta 6 in the other.