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A gene inactivation system (GIS) acting in meiosis of a duplicated strain of Aspergillus nidulans

Marialba A.A. de Castro-Prado^I; Tânia M.A.D. Zucchi^II

^IDepartamento de Biologia Celular e Genética, Universidade Estadual de Maringá, Av. Colombo 3690, 87020-900 Maringá, PR, Brasil
^IIInstituto de Ciências Biomédicas, Universidade de São Paulo, Av. Prof. Lineu Prestes 1374, 05508-900 São Paulo, SP, Brasil. Telephone: 55-11-818-7264. Fax: 55-11-818-7417. Send correspondence to T.M.A.D.Z.

ABSTRACT

This paper deals with a gene inactivation system (GIS) that is able to alter duplicate genes in A. nidulans, through methylation of cytosine residues, probably acting even after karyogamy. The gene reactivation can be induced or spontaneous. The normal parental class, observed in some crosses, indicates clearly that GIS can act not only over the period ranging from fertilization to karyogamy as repeat induced point mutation (RIP) does but also in the diploid nucleus, before meiosis.
These results show a gene inactivation process, by methylation, triggered by the presence of an extra DNA segment in the genome of Aspergillus nidulans.

Keywords: gene inactivation system; meiosis; Aspergillus nidulans.

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