Baudoin C, Van der Flier A, Borradori L, Sonnenberg A
Department of Cell Biology, The Netherlands Cancer Institute, Amsterdam, The Netherlands.
Cell Adhes Commun. 1996 Jul;4(1):1-11. doi: 10.3109/15419069609010759.
We have determined the genomic organization of the 3'-region of the murine beta 1 gene and cloned the murine beta 1D integrin splice variant. Overlapping genomic clones encompassing the region of the beta 1D-specific exons were isolated from a phage lambda FIXII library, mapped and partially sequenced. All of the exon-intron junctions identified in the murine beta 1 gene fit with the consensus splice donor and acceptor sequences and occur at the same positions as in their human counterparts. cDNA clones for the beta 1D integrin were isolated from a murine skeletal muscle library. The human and murine beta 1D sequences are conserved at the nucleotide (93%) and amino acid (100%) level, suggesting an important role of this muscle-specific variant throughout mammalian phylogenesis. In contrast, murine sequences for beta 1B are very different from human beta 1B at both the nucleotide as well as amino acid level. Moreover, no specific polyadenylation signal for the beta 1B variant could be identified in genomic clones, suggesting that this variant is not present in the mouse. Finally, we were not able to identify a murine beta 1C splice variant by sequencing analysis, Southern hybridization techniques or polymerase chain reaction of mRNA from platelets. These findings indicate that the beta 1B and beta 1C variants emerged relatively late in the phylogenesis of the beta 1 integrin family.
我们已经确定了小鼠β1基因3'区域的基因组结构，并克隆了小鼠β1D整合素剪接变体。从噬菌体λFIXII文库中分离出包含β1D特异性外显子区域的重叠基因组克隆，进行定位并部分测序。在小鼠β1基因中鉴定出的所有外显子-内含子连接均符合共有剪接供体和受体序列，且与人类对应序列中的位置相同。从鼠骨骼肌文库中分离出β1D整合素的cDNA克隆。人类和小鼠的β1D序列在核苷酸水平（93%）和氨基酸水平（100%）上保守，表明这种肌肉特异性变体在整个哺乳动物系统发育中具有重要作用。相比之下，小鼠β1B的序列在核苷酸和氨基酸水平上与人类β1B都非常不同。此外，在基因组克隆中未鉴定出β1B变体的特异性聚腺苷酸化信号，表明该变体在小鼠中不存在。最后，通过测序分析、Southern杂交技术或血小板mRNA的聚合酶链反应，我们未能鉴定出小鼠β1C剪接变体。这些发现表明，β1B和β1C变体在β1整合素家族的系统发育中出现得相对较晚。
