Neurospora Spore Killers Sk-2 and Sk-3 Suppress Meiotic Silencing by Unpaired DNA

Neurospora spore killers Sk-2 and Sk-3 suppress meiotic silencing by unpaired DNA.

In Neurospora crassa, pairing of homologous DNA segments is monitored during meiotic prophase I. Any genes not paired with a homolog, as well as any paired homologs of that gene, are silenced during the sexual phase by a mechanism known as meiotic silencing by unpaired DNA (MSUD). Two genes required for MSUD have been described previously: sad-1 (suppressor of ascus dominance), encoding an RNA-...

Meiotic Silencing by Unpaired DNA

The silencing of gene expression by segments of DNA present in excess of the normal number is called cosuppression in plants and quelling in fungi. We describe a related process, meiotic silencing by unpaired DNA (MSUD). DNA unpaired in meiosis causes silencing of all DNA homologous to it, including genes that are themselves paired. A semidominant Neurospora mutant, Sad-1, fails to perform MSUD...

Novel proteins required for meiotic silencing by unpaired DNA (MSUD) and siRNA generation in Neurospora crassa

Novel proteins required for meiotic silencing by unpaired DNA and siRNA generation in Neurospora crassa.

During meiosis in the filamentous fungus Neurospora crassa, unpaired genes are identified and silenced by a process known as meiotic silencing by unpaired DNA (MSUD). Previous work has uncovered six proteins required for MSUD, all of which are also essential for meiotic progression. Additionally, they all localize in the perinuclear region, suggesting that it is a center of MSUD activity. Never...

Sex and the single gene: Meiotic silencing by unpaired DNA

In the fungus Neurospora crassa, crosses made between normal sequence strains and some translocation strains can yield three kinds of progeny: normal sequence (like one parent), translocation sequence (like the other parent) and a novel class that is duplicated for the translocated segment. The duplication progeny arise when one component of the translocation segregates with a normal sequence c...