Kunau W H, Hartig A
Abteilung Zellbiochemie, Medizinische Fakultät, Ruhr-Universität, Bochum, Germany.
Antonie Van Leeuwenhoek. 1992 Aug;62(1-2):63-78. doi: 10.1007/BF00584463.
The observation that peroxisomes of Saccharomyces cerevisiae can be induced by oleic acid has opened the possibility to investigate the biogenesis of these organelles in a biochemically and genetically well characterized organism. Only few enzymes have been identified as peroxisomal proteins in Saccharomyces cerevisiae so far; the three enzymes involved in beta-oxidation of fatty acids, enzymes of the glyoxylate cycle, catalase A and the PAS3 gene product have been unequivocally assigned to the peroxisomal compartment. However, more proteins are expected to be constituents of the peroxisomes in Saccharomyces cerevisiae. Mutagenesis of Saccharomyces cerevisiae cells gave rise to mutants unable to use oleic acid as sole carbon source. These mutants could be divided in two groups: those with defects in structural genes of beta-oxidation enzymes (fox-mutants) and those with defects in peroxisomal assembly (pas-mutants). All fox-mutants possess morphologically normal peroxisomes and can be assigned to one of three complementation groups (FOX1, 2, 3). All three FOX genes have been cloned and characterized. The pas-mutants isolated are distributed among 13 complementation groups and represent 3 different classes: peroxisomes are either morphologically not detectable (type I) or present but non-proliferating (type II). Mislocalization concerns all peroxisomal proteins in cells of these two classes. The third class of mutants contains peroxisomes normal in size and number, however, distinct peroxisomal matrix proteins are mislocalized (type III). Five additional complementation groups were found in the laboratory of H.F. Tabak. Not all PAS genes have been cloned and characterized so far, and only for few of them the function could be deduced from sequence comparisons. Proliferation of microbodies is repressed by glucose, derepressed by non-fermentable carbon sources and fully induced by oleic acid. The regulation of four genes encoding peroxisomal proteins (PAS1, CTA1, FOX2, FOX3) occurs on the transcriptional level and reflects the morphological observations: repression by glucose and induction by oleic acid. Moreover, trans-acting factors like ADR1, SNF1 and SNF4, all involved in derepression of various cellular processes, have been demonstrated to affect transcriptional regulation of genes encoding peroxisomal proteins. The peroxisomal import machinery seems to be conserved between different organisms as indicated by import of heterologous proteins into microbodies of different host cells. In addition, many peroxisomal proteins contain C-terminal targeting signals. However, more than one import route into peroxisomes does exist.(ABSTRACT TRUNCATED AT 400 WORDS)
酿酒酵母的过氧化物酶体可被油酸诱导这一发现，为在一个生物化学和遗传学特征明确的生物体中研究这些细胞器的生物发生开辟了可能性。到目前为止，在酿酒酵母中仅鉴定出少数几种酶作为过氧化物酶体蛋白；参与脂肪酸β-氧化的三种酶、乙醛酸循环的酶、过氧化氢酶A和PAS3基因产物已被明确归为过氧化物酶体区室。然而，预计酿酒酵母的过氧化物酶体还有更多蛋白质成分。对酿酒酵母细胞进行诱变产生了无法将油酸作为唯一碳源利用的突变体。这些突变体可分为两组：一组是β-氧化酶结构基因有缺陷的突变体（fox突变体），另一组是过氧化物酶体组装有缺陷的突变体（pas突变体）。所有fox突变体的过氧化物酶体形态正常，可分为三个互补组之一（FOX1、2、3）。所有三个FOX基因均已被克隆和表征。分离出的pas突变体分布在13个互补组中，代表3种不同类型：过氧化物酶体要么在形态上无法检测到（I型），要么存在但不增殖（II型）。这两类细胞中的所有过氧化物酶体蛋白都存在定位错误。第三类突变体的过氧化物酶体大小和数量正常，然而，不同的过氧化物酶体基质蛋白存在定位错误（III型）。在H.F. Tabak实验室还发现了另外五个互补组。到目前为止，并非所有PAS基因都已被克隆和表征，只有少数几个基因的功能可通过序列比较推断出来。微体的增殖受到葡萄糖的抑制，被不可发酵碳源解除抑制，并被油酸完全诱导。四个编码过氧化物酶体蛋白的基因（PAS1、CTA1、FOX2、FOX3）的调控发生在转录水平，反映了形态学观察结果：受葡萄糖抑制，被油酸诱导。此外，已证明参与多种细胞过程去抑制的反式作用因子，如ADR1、SNF1和SNF4，会影响编码过氧化物酶体蛋白的基因的转录调控。正如将异源蛋白导入不同宿主细胞的微体所表明的那样，过氧化物酶体的导入机制在不同生物体之间似乎是保守的。此外，许多过氧化物酶体蛋白含有C末端靶向信号。然而，确实存在不止一条进入过氧化物酶体的途径。（摘要截选至400字）
