Torres-Guzmán J C, Domínguez A
Departamento de Microbiología y Genética, Universidad de Salamanca, Spain.
Mol Cell Biol. 1997 Nov;17(11):6283-93. doi: 10.1128/MCB.17.11.6283.
The dimorphic fungus Yarrowia lipolytica grows to form hyphae either in rich media or in media with GlcNAc as a carbon source. A visual screening, called FIL (filamentation minus), for Y. lipolytica yeast growth mutants has been developed. The FIL screen was used to identify three Y. lipolytica genes that abolish hypha formation in all media assayed. Y. lipolytica HOY1, a gene whose deletion prevents the yeast-hypha transition both in liquid and solid media, was characterized. HOY1 is predicted to encode a 509-amino-acid protein with a homeodomain homologous to that found in the chicken Hox4.8 gene. Analysis of the protein predicts a nuclear location. These observations suggest that Hoy1p may function as a transcriptional regulatory protein. In disrupted strains, reintroduction of HOY1 restored the capacity for hypha formation. Northern blot hybridization revealed the HOY1 transcript to be approximately 1.6 kb. Expression of this gene was detected when Y. lipolytica grew as a budding yeast, but an increase in its expression was observed by 1 h after cells had been induced to form hyphae. The possible functions of HOY1 in hyphal growth and the uses of the FIL screen to identify morphogenetic regulatory genes from heterologous organisms are discussed.
解脂耶氏酵母这种双态真菌在富含营养的培养基中或在以N-乙酰葡糖胺作为碳源的培养基中生长时会形成菌丝。一种用于筛选解脂耶氏酵母酵母生长突变体的视觉筛选方法——FIL（丝状化缺陷）已经开发出来。FIL筛选被用于鉴定三个在所有检测培养基中都能消除菌丝形成的解脂耶氏酵母基因。对解脂耶氏酵母HOY1基因进行了表征，该基因的缺失会阻止其在液体和固体培养基中从酵母向菌丝的转变。预测HOY1编码一个含有509个氨基酸的蛋白质，其同源异型结构域与鸡的Hox4.8基因中的同源异型结构域相似。对该蛋白质的分析预测其定位于细胞核。这些观察结果表明Hoy1p可能作为一种转录调节蛋白发挥作用。在基因敲除菌株中，重新引入HOY1可恢复菌丝形成能力。Northern印迹杂交显示HOY1转录本约为1.6 kb。当解脂耶氏酵母以出芽酵母形式生长时可检测到该基因的表达，但在细胞被诱导形成菌丝1小时后观察到其表达增加。本文讨论了HOY1在菌丝生长中的可能功能以及FIL筛选在从异源生物体中鉴定形态发生调节基因方面的用途。
