Navigation Links
Single molecular 'mark' seen as pivotal for genome compaction in spores and sperm

In higher order animals, genetic information is passed from parents to offspring via sperm or eggs, also known as gametes. In some single-celled organisms, such as yeast, the genes can be passed to the next generation in spores. In both reproductive strategies, major physical changes occur in the genetic material after it has been duplicated and then halved on the way to the production of mature gametes or spores. Near the end of the process, the material ?called chromatin, the substructure of chromosomes ?becomes dramatically compacted, reduced in volume to as little as five percent of its original volume.

Researchers at The Wistar Institute, studying the mechanisms that control how the genetic material is managed during gamete production, have now identified a single molecule whose presence is required for genome compaction. Their experiments showed that the molecule "marks" the chromatin just prior to compaction and that its presence is mandatory for successful compaction. Additionally, after first noting the molecule's activity during the production of yeast spores, the scientists saw the same activity during the creation of sperm in fruit flies and mice, suggesting that the mechanisms governing genome compaction are evolutionarily ancient, highly conserved in species whose lineages diverged long ago. A report on the new study appears in the September 15 issue of Genes & Development. A "Perspectives" review in the same issue expands on the significance of the findings.

"This molecular mark is required at a critical time leading up to genome compaction in spores and sperm," says Shelley L. Berger, Ph.D., the Hilary Koprowski Professor at The Wistar Institute and senior author on the study. "Also, there seems to be a similarity in the way the mark is used in organisms as different from each other as yeast and mammals, suggesting that compaction has been important throughout evolution."

Berger speculates that compaction might answer a nu mber of important biological purposes.

"During the time the DNA is single-stranded, as it is in the gametes, it's much more susceptible to breaks and mutations," she says. "Compaction may keep the genome resistant to damage of all kinds. This is critical ?if the single-stranded DNA in gametes breaks, it can fall apart and possibly reassemble itself in devastating translocations."

She notes that normal double-stranded DNA, on the other hand, has the ability to repair breaks in one of its single strands by using the chemical bases in the companion strand as a reference. Bases in DNA pair only in predetermined combinations, so that one strand can serve as a template for the other.

"Compaction might also affect sperm fertility and function in the higher organisms, and thus the propagation of the species," says Thanuja Krishnamoorthy, Ph.D., lead author on the study. "It's vital that we better understand genome compaction during the production of mature sperm."

The molecule in question is a phosphorous molecule that modifies a histone. Histones are relatively small proteins around which DNA is coiled to create structures called nucleosomes. Compact strings of nucleosomes, then, form into chromatin, the substructure of chromosomes.

To test the team's observations, Krishnamoorthy performed an experiment in yeast in which she altered the histone's chemical composition at a single point, the point at which the molecule attaches to, or marks, the histone. The results were clear and compelling: With the alteration, the molecule was unable to attach to the histone, and compaction was severely limited.

"We saw a significant increase in genomic volume in the resulting yeast spores, as though the compaction had been lost," Berger says. "The frequency of successful spore creation was also lowered significantly."


Source:The Wistar Institute

Related biology news :

1. Novel Asthma Study Shows Multiple Genetic Input Required; Single-gene Solution Shot Down
2. Single stem cells from bone heal a broken heart
3. Successful Test Of Single Molecule Switch Opens The Door To Biomolecular Electronics
4. Single-donor Islet Transplantation Procedure Shows Promise For Patients With Type 1 Diabetes
5. Single gene is genetic switch for fly sexual behavior
6. Single microRNA causes cancer in transgenic mouse
7. Single cell amoeba increases MRSA numbers 1000- fold
8. Single molecule extends fat mice lives by reversing gene pathways associated with disease in obese
9. Scientists ID molecular switch in liver that triggers harmful effects of saturated and trans fats
10. Source of molecular triggers in cutaneous T cell lymphoma identified
11. Plants, animals share molecular growth mechanisms
Post Your Comments:

(Date:10/29/2015)... , Oct. 29, 2015 Today, ... a partnership with 2XU, a global leader in ... a smart hat with advanced bio-sensing technology. The ... athletes to monitor key biometrics to improve overall ... partnership, the two companies will bring together the most ...
(Date:10/27/2015)... SAN JOSE, Calif. , Oct. 27, 2015 /PRNewswire/ ... human interface solutions, today announced that Google has adopted ... family of touch controller solutions to power its newest ... Nexus 6P by Huawei. --> ... ecosystem partners like Google to provide strategic collaboration in ...
(Date:10/26/2015)... 26, 2015  Delta ID Inc., a company focused ... and PC devices, announced its ActiveIRIS® technology powers the ... F-02H launched by NTT DOCOMO, INC in ... second smartphone to include iris recognition technology, after a ... F-04G in May 2015, world,s first smartphone to have ...
Breaking Biology News(10 mins):
(Date:11/25/2015)... Nov. 25, 2015 /PRNewswire/ - Aeterna Zentaris Inc. (NASDAQ: ... business and prospects remain fundamentally strong and highlights ... doxorubicin) recently received DSMB recommendation to continue the ... review of the final interim efficacy and safety ... Endpoint in men with heavily pretreated castration- and ...
(Date:11/25/2015)... ... November 25, 2015 , ... Jessica Richman and ... early in their initial angel funding process. Now, they are paying it forward ... make early stage investments in the microbiome space. In this, they join ...
(Date:11/24/2015)... SAN DIEGO , Nov. 24, 2015 Halozyme Therapeutics, ... Jaffray Healthcare Conference in New York on ... Dr. Helen Torley , president and CEO, will provide a ... New York at 1:00 p.m. ET/10:00 a.m. ... communication and investor relations, will provide a corporate overview. --> ...
(Date:11/24/2015)... 2015 /PRNewswire/ - Aeterna Zentaris Inc. (NASDAQ:  AEZS) (TSX: AEZ) ... of the Toronto Stock Exchange, confirms that as of ... corporate developments that would cause the recent movements in ... --> About Aeterna Zentaris Inc. ... Aeterna Zentaris is a specialty biopharmaceutical company engaged ...
Breaking Biology Technology: