Molecular Structure and Function of Crystallins

眼睛的组织依赖于严格调控的发育途径和特化蛋白质家族。这些包括晶状体的晶状体蛋白。我们已经证明，在人类和其他物种中，晶状体蛋白是通过从眼睛中预先存在的蛋白质中招募基因的过程而产生的。因此，晶体蛋白是一种多功能蛋白质。虽然许多种类的晶体蛋白的起源和功能已被阐明，但主要的b-和g-晶体蛋白的起源和功能仍不清楚。GS-晶体蛋白是成人晶状体中主要的BG-晶体蛋白。GS基因的去除会导致正常纤维细胞成熟的中断。酵母双杂交实验正在进行中，以确定GS的相互作用伙伴。小鼠GS-晶体蛋白的核磁共振结构分析表明，柔性连接区和N-末端区域在提供蛋白质溶解度的熵贡献中起着重要作用。与OPJ白内障相关的GS的结构也在确定中。 在人类和动物模型中，G-晶体蛋白都与白内障有关。我们发现，小鼠3号白内障是由于内源性逆转录病毒插入到GE-晶体蛋白基因中，产生了异常蛋白。与类似的突变相比，N3的表型较轻。这至少部分是由于3号突变体中GE水平的抑制，可能是由于逆转录病毒LTR的影响。然而，很明显，不同品系的小鼠的表型受遗传背景的影响。这为不同基因的相互作用在不同的个体中产生不同的疾病结果提供了一个模型。 我们还定义了一个重要的动物模型-斑马鱼的晶状体蛋白谱系，并表明在该物种中存在AB-晶状体蛋白的基因复制和功能分离。这表明了脊椎动物进化过程中多样性和复杂性产生的一个重要机制。

Tissues of the eye depend on closely regulated developmental pathways and families of specialized proteins. These include the crystallins of the lens. We have shown that in humans and other species, crystallins have arisen by a process of gene recruitment from proteins with pre-existing roles in the eye. Thus crystallins are multifunctional proteins. While the origins and functions of many classes of crystallins have been elucidated, those of the major groups of b- and g-crystallins are still unknown. gS-crystallin is the major bg-crystallin in the adult human lens. Ablation of the gene for gS leads to disruption of normal fiber cell maturation. Yeast 2-hybrid experiments to determine interaction partners for gS are in progress. NMR structure analysis of mouse gS-crystallin suggests important roles for flexible linker and N-terminal regions in providing entropic contributions to protein solubility. The structure of gS associated with the Opj cataract is also being determined. g-Crystallins are associated with cataract in both human and animal models. We have found that the murine No3 cataract is due to insertion of an endogenous retrovirus into the gene for gE-crystallin, giving rise to an aberrant protein. The phenotype of No3 is mild compared with similar mutations. This is at least partly due to suppression of levels for gE in the No3 mutant, probably due to effects of the retroviral LTR. However it is also clear that the phenotype is modulated by the genetic background in different mouse strains. This provides a model for the way in which interactions of different genes can produce different disease outcomes in different individuals. We have also defined the repertoire of crystallins in an important animal model, the zebrafish and have shown that in this species there has been a gene duplication and separation of functions in aB-crystallin. This demonstrates an important mechanism for the generation of diversity and complexity in vertebrate evolution.