Inactivation of the gene coding for the 30.4-kDa subunit of respiratory chain NADH dehydrogenase: is the enzyme essential for Neurospora?

• Type: Article in International Scientific Journal
• Date: 1998

Authors

duarte, m (Author) Other; mota, n (Author) Other; pinto, l (Author) Other; videira, a (Author) ICBAS

Journal

Title: Molecular and General Genetics

Vol. 257

Pages: 368-375

ISSN: 0026-8925

Publisher: Springer

Indexing

ISI Web of Knowledge - 15 Citations

Scopus - 14 Citations

Other information

Authenticus ID: P-001-8M3

DOI: 10.1007/s004380050659

Abstract (EN): We have isolated and characterised the nuclear gene that codes for the 30.4-kDa subunit of the peripheral arm of complex I from Neurospora crassa. The single-copy gene was localised on chromosome VI of the fungal genome by restriction fragment length polymorphism mapping. An extra copy of the gene was introduced into a strain of N. crassa by transformation. This strain was crossed with another strain in order to inactivate, by repeat-induced point mutations, both copies of the duplication carried by the parental transformant. Ascospore progeny from the cross were analysed and a mutant strain lacking the 30.4-kDa protein, nuo30.4, was isolated and further characterised. The mutant appears to assemble the membrane arm of complex I, while formation of the peripheral arm is prevented. Nevertheless, the mutant grows reasonably well - indicating that this well conserved protein is not essential for vegetative growth - and is able to mate with other strains both as male or female. Strains with multiple mutations are readily obtained from heterozygous crosses between different complex I mutants of N. crassa. On the other hand, homozygous crosses between several mutants, including nuo30.4, fail to produce ascospores. These results suggest that complex I plays an essential role during the sexual phase of the life cycle of the fungus.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 8