Saupe S J, Glass N L
Botany Department, University of British Columbia, Vancouver, Canada.
Genetics. 1997 Aug;146(4):1299-309. doi: 10.1093/genetics/146.4.1299.
In filamentous fungi, the ability to form a productive heterokaryon with a genetically dissimilar individual is controlled by specific loci termed het loci. Only strains homozygous for all het loci can establish a heterokaryon. In Neurospora crassa, 11 loci, including the mating-type locus, regulate the capacity to form heterokaryons. An allele of the het-c locus (het-cOR) of N. crassa has been previously characterized and encodes a nonessential 966 amino acid glycine-rich protein. Herein, we describe the genetic and molecular characterization of two hei-c alleles, het-cPA and het-cOR, that have a different specificity from that of het-cOR, showing that vegetative incompatibility is mediated by multiple alleles at het-c. By constructing chimeric alleles, we show that het-c specificity is determined by a highly variable domain of 34-48 amino acids in length. In this regard, het-c is similar to loci that regulate recognition in other species, such as the (S) self-incompatibility locus in plants, the sexual compatibility locus in basidiomycetes and the major histocompatibility complex (MHC) genes in vertebrates.
在丝状真菌中，与基因不同的个体形成有功能的异核体的能力由称为het位点的特定基因座控制。只有所有het基因座均为纯合的菌株才能建立异核体。在粗糙脉孢菌中，包括交配型基因座在内的11个基因座调节形成异核体的能力。粗糙脉孢菌的het-c基因座（het-cOR）的一个等位基因先前已被鉴定，编码一种非必需的富含甘氨酸的966个氨基酸的蛋白质。在此，我们描述了两个hei-c等位基因het-cPA和het-cOR的遗传和分子特征，它们与het-cOR具有不同的特异性，表明营养体不亲和性由het-c的多个等位基因介导。通过构建嵌合等位基因，我们表明het-c特异性由长度为34 - 48个氨基酸的高度可变结构域决定。在这方面，het-c类似于调节其他物种识别的基因座，如植物中的（S）自交不亲和基因座、担子菌中的性亲和基因座以及脊椎动物中的主要组织相容性复合体（MHC）基因。
