Sinha D, Esumi N, Jaworski C, Kozak C A, Pierce E, Wistow G
Section on Molecular Structure and Function, National Eye Institute, National Institutes of Health, Bethesda, MD 20892-2740, USA.
Mol Vis. 1998 Apr 30;4:8.
[gamma]-Crystallins are major structural proteins of the eye lens. While other crystallins have revealed distinct non-lens functions and patterns of expression, [gamma]-crystallins have generally appeared to be the most lens-specific of the crystallins. Here we examine the mouse [gamma]S-crystallin ([gamma]S) gene and its expression.
The cDNA and gene for mouse [gamma]S were cloned and sequenced. The Crygs gene was mapped using genetic crosses. Expression patterns in mouse and cow were examined by northern blot, PCR and western blot using a specific peptide antibody.
The Crygs gene was sequenced and mapped to mouse chromosome 16, at or near the locus for the genetic cataract Opj. Northern blots of tissues from new born mice, showed lens specific expression of [gamma]S. However, in the mature mouse eye there was, in addition, clear non-lens expression of [gamma]S. In the adult bovine eye RT-PCR shows that [gamma]S is expressed in lens, retina and cornea. A peptide antibody directed against [gamma]S detects bands of the expected size in western blots of mouse lens and in 33 day old mouse retina.
These results suggest that [gamma]-crystallins have a non-crystallin role outside the lens, one which may predate the lens in evolutionary terms. Non-lens expression seems to increase with age in young mice, hinting that [gamma]S may have a role similar to that of a stress protein in tissues of the eye, perhaps related to accumulating insults resulting from light exposure.
γ-晶体蛋白是晶状体的主要结构蛋白。虽然其他晶体蛋白已显示出不同的非晶状体功能和表达模式，但γ-晶体蛋白通常似乎是晶体蛋白中最具晶状体特异性的。在此，我们研究小鼠γS-晶体蛋白（γS）基因及其表达。
克隆并测序小鼠γS的cDNA和基因。利用遗传杂交对Crygs基因进行定位。通过Northern印迹、PCR和使用特异性肽抗体的Western印迹检测小鼠和牛中的表达模式。
对Crygs基因进行了测序并定位到小鼠16号染色体上，位于遗传性白内障Opj基因座处或其附近。新生小鼠组织的Northern印迹显示γS有晶状体特异性表达。然而，在成熟小鼠眼中，此外γS还有明显的非晶状体表达。在成年牛眼中，RT-PCR显示γS在晶状体、视网膜和角膜中表达。针对γS的肽抗体在小鼠晶状体和33日龄小鼠视网膜的Western印迹中检测到预期大小的条带。
这些结果表明，γ-晶体蛋白在晶状体之外具有非晶体蛋白的作用，从进化角度来看，这一作用可能早于晶状体的出现。在幼鼠中，非晶状体表达似乎随年龄增加，这表明γS可能在眼组织中具有类似于应激蛋白的作用，可能与光暴露导致的累积损伤有关。
