Mitochondrial Genes in Aspergillus

Abstract

The mitochondrial genome of Aspergillus nidulans, a circular molecule about 32 kb long, is one of the smallest among fungal mtDNAs (López-Pérez and Turner 1975; Bernard and Küntzel 1976). It shares with the two times larger mtDNA of Neurospora crassa the basic features of tRNA-rRNA gene organization: The contiguous S-rRNA (small ribosomal subunit RNA) gene is separated from the split L-rRNA gene by a long spacer containing the gene for cytochrome oxidase subunit III (COIII) and a tRNA gene cluster, and the L-rRNA gene is followed by a second tRNA gene cluster (de Vries et al. 1979; Hahn et al. 1979; Heckman and RajBhandary 1979; Agsteribbe et al. 1980; Lazarus et al. 1980b; Macino et al. 1980).

Sequencing of tRNA gene clusters on A. nidulans mtDNA (Köchel et al. 1981) has revealed a close affinity of tRNA sequences and tRNA gene orders between A. nidulans and N. crassa. On the other hand, it is also evident that some tRNA genes have been translocated, since the separation of the two organisms and preliminary gene-mapping studies suggest that the order of protein genes is not entirely conserved in the two fungi (Macino et al. 1980).

More sequence data are needed to better understand the evolutionary processes leading to the various types of present-day mtDNAs, and sequence analyses of universally occurring genes like those coding for rRNAs may aid in the study of the origin of mitochondria. Here we summarize our knowledge of the structure and dynamics of mtDNA in the genus Aspergillus...