Sterol effects and sites of sterol accumulation in Caenorhabditis elegans:: developmental requirement for 4α-methyl sterols
Sterol effects and sites of sterol accumulation in Caenorhabditis elegans:: developmental requirement for 4α-methyl sterols
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DOI：
10.1194/jlr.m200323-jlr200
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发表时间：
2003-01-01
影响因子：
6.5
通讯作者：
Lenard, J
中科院分区：
文献类型：
--
作者：
Merris, M;Wadsworth, WG;Lenard, J
秀丽隐杆线虫需要固醇，通常以胆固醇形式提供，但这是经过酶修饰的，可以用不同的固醇替代。甾醇剥夺减少育雏大小和成人的增长在第一代，完全，可逆，逮捕的增长，在第二代幼虫。在一代甾醇剥夺后，10 ng/ml胆固醇允许延迟产卵，但完全生长需要300 ng/ml。C.线虫合成两种不寻常的4 α-甲基甾醇（4 MS），但每种4 MS作为唯一的甾醇仅支持有限的生长。然而，在1，000 ng 4 MS中仅添加10 ng胆固醇即可恢复完全生长和产卵，这表明4 MS和未甲基化甾醇都是发育所需的。Filipin染色甾醇只有几个特定的细胞：排泄腺细胞，两个两栖插座细胞，两个phasmid插座细胞，在男性，骨针插座细胞。在摄食动物的咽部和肠道中也存在从近端到远端梯度的类固醇。这种非随机的甾醇分布，低浓度的要求，和4 MS的影响，认为甾醇不太可能用于细胞膜的整体结构修饰，但可能需要作为激素前体和/或发育效应。
Caenorhabditis elegans requires sterol, usually supplied as cholesterol, but this is enzymatically modified, and different sterols can substitute. Sterol deprivation decreased brood size and adult growth in the first generation, and completely, reversibly, arrested growth as larvae in the second. After one generation of sterol deprivation, 10 ng/ml cholesterol allowed delayed laying of a few eggs, but full growth required 300 ng/ml. C. elegans synthesizes two unusual 4alpha-methyl sterols (4MSs), but each 4MS supported only limited growth as the sole sterol. However, addition of only 10 ng of cholesterol to 1,000 ng of 4MS restored full growth and egg-laying, suggesting that both a 4MS and an unmethylated sterol are required for development. Filipin stained sterols in only a few specific cells: the excretory gland cell, two amphid socket cells, two phasmid socket cells and, in males, spicule socket cells. Sterols were also present in the pharynx and in the intestine of feeding animals in a proximal-to-distal gradient. This non-random sterol distribution, the low concentration requirements, and the effects of 4MSs argues that sterols are unlikely to be used for bulk structural modification of cell membranes, but may be required as hormone precursors and/or developmental effectors.