For yeast, a DNA break ensures sex switch for a grandchild

November 08, 2004

New work has established a molecular mechanism to explain how fission yeast cells manage to switch the mating type of a certain proportion of individuals over the course of two generations. This genetic trick has been long studied but poorly understood. Researchers now report that yeast achieve the switch by enacting a special kind of programmed DNA break at a specific genomic site that controls mating type, the yeast equivalent of gender.

When yeast cells divide, their progeny receive the same genomic DNA, yet the fate of the cells of the next generation will not be identical. One of the two daughter cells will produce a granddaughter cell that has switched its sexual mating type. Two decades ago, researchers proposed that a chromosomal imprint at the mating-type locus was responsible for generating two rounds of asymmetric division. Now Benoit Arcangioli's group at the Pasteur Institute in Paris, France, has identified a new imprinting mechanism that controls sexual switching in yeast.

The French group has now demonstrated that the genomic DNA at the mating-type locus of the yeast Schizosaccharomyces pombe is marked by a simple break on one strand of the DNA. One of the daughter cells will receive this nicked DNA upon cell division, and the nick serves as a signal for sex switching in the next generation. The researchers showed that the nick is site specific but sequence independent. The single-strand break is protected by 3'-OH and 5'-OH modification of the two DNA ends, and there is not loss of nucleotides.

In their new work, the authors propose that this represents the first example of an imprinting event that is due to a simple single-strand break. The discovery has general implications for how DNA can be marked for asymmetric inheritance that can affect cell destiny.
-end-
Atanas Kaykov and Benoit Arcangioli: "A Programmed Strand-Specific and Modified Nick in S. pombe Constitutes a Novel Type of Chromosomal Imprint"

Publishing in Current Biology, Volume 14, Number 21, November 9, 2004, pages 1924-1928.

Cell Press

Related DNA Articles from Brightsurf:

A new twist on DNA origami
A team* of scientists from ASU and Shanghai Jiao Tong University (SJTU) led by Hao Yan, ASU's Milton Glick Professor in the School of Molecular Sciences, and director of the ASU Biodesign Institute's Center for Molecular Design and Biomimetics, has just announced the creation of a new type of meta-DNA structures that will open up the fields of optoelectronics (including information storage and encryption) as well as synthetic biology.

Solving a DNA mystery
''A watched pot never boils,'' as the saying goes, but that was not the case for UC Santa Barbara researchers watching a ''pot'' of liquids formed from DNA.

Junk DNA might be really, really useful for biocomputing
When you don't understand how things work, it's not unusual to think of them as just plain old junk.

Designing DNA from scratch: Engineering the functions of micrometer-sized DNA droplets
Scientists at Tokyo Institute of Technology (Tokyo Tech) have constructed ''DNA droplets'' comprising designed DNA nanostructures.

Does DNA in the water tell us how many fish are there?
Researchers have developed a new non-invasive method to count individual fish by measuring the concentration of environmental DNA in the water, which could be applied for quantitative monitoring of aquatic ecosystems.

Zigzag DNA
How the cell organizes DNA into tightly packed chromosomes. Nature publication by Delft University of Technology and EMBL Heidelberg.

Scientists now know what DNA's chaperone looks like
Researchers have discovered the structure of the FACT protein -- a mysterious protein central to the functioning of DNA.

DNA is like everything else: it's not what you have, but how you use it
A new paradigm for reading out genetic information in DNA is described by Dr.

A new spin on DNA
For decades, researchers have chased ways to study biological machines.

From face to DNA: New method aims to improve match between DNA sample and face database
Predicting what someone's face looks like based on a DNA sample remains a hard nut to crack for science.

Read More: DNA News and DNA Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.