Transcription during mitosis could cause a real mess. In most organisms, mitosis is "open": that is the nuclear membrane breaks down. As a result of disruption of the normal compartmentalization ribosomes might begin translation prior to splicing out of introns. You should see that this would create a mess of defective protein products.

In most organisms transcription is interrupted during mitosis. Indeed, even ongoing transcripts are aborted (See Shermoen and O'Farrell,1991). Mitosis is closed (nuclear membrane remains intact) in the budding yeast, S. cerevisiae, and in this organism transcription continues during mitosis. There are a variety of different types of organization of mitosis in yeasts and other single celled organisms, and it would be interesting to know whether there was widespread correlation of inhibition of transcription with an open mitosis and visa versa - if this is known, I am not aware of it.

I don't think it's ever possible to completely silence transcription of the entire genome, but rather it depends on a series of events that are triggered using the epigenome to create a specific event.

Hi Ben,

In a discussion with my biology professor, he indicated that gene expression is silenced during mitosis. However, it is difficult to imagine, as you mentioned, that the entire genome is completely silenced during mitosis; the cell must still maintain some functions.

I recently found an article, attached, that indicates that cyclin B1 gene is actively transcribed during mitosis; so i am sure there are plenty of other genes that are transcribed. However, I still believe that transcription is greatly reduced.

Thanks

http://www.nature.com/embor/journal/v2/n11/abs/embor298.html

Transcription during mitosis could cause a real mess. In most organisms, mitosis is "open": that is the nuclear membrane breaks down. As a result of disruption of the normal compartmentalization ribosomes might begin translation prior to splicing out of introns. You should see that this would create a mess of defective protein products.

In most organisms transcription is interrupted during mitosis. Indeed, even ongoing transcripts are aborted (See Shermoen and O'Farrell,1991). Mitosis is closed (nuclear membrane remains intact) in the budding yeast, S. cerevisiae, and in this organism transcription continues during mitosis. There are a variety of different types of organization of mitosis in yeasts and other single celled organisms, and it would be interesting to know whether there was widespread correlation of inhibition of transcription with an open mitosis and visa versa - if this is known, I am not aware of it.

I initially thought that gene expression would be occurring during mitosis due to this idea of mitotic check points to ensure the integrity of the separation of chromosomes; how else may many of these proteins arise in the cell?

An indeed it has been shown that for active translation is required for maintenance of the mitotic spindle(article attached).

However, it would make sense that translation for events outside of mitosis would be shutdown.

Thanks for the input

http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0013037

Dear Michael and All, This article (referencing Cell's December 19 publication) speaks to a lot of disease etiology due to the silencing of 'beneficial' events allowing instead expression ('evolution') of 'dis-ease,' more specifically, the breakdown of communication between mitochondria and the nucleus. Key excerpts from the article, http://hms.harvard.edu/news/genetics/new-reversible-cause-aging-12-19-13?:

"Previous studies...showed that one of these genes, SIRT1, was activated by the compound resveratrol, which is found in grapes, red wine and certain nuts."

"...as we age, levels of the initial chemical NAD decline. Without sufficient NAD, SIRT1 loses its ability to keep tabs on HIF-1. Levels of HIF-1 escalate and begin wreaking havoc on the otherwise smooth cross-genome communication. Over time, the research team found, this loss of communication reduces the cell's ability to make energy, and signs of aging and disease become apparent."

"Gomes found that by administering an endogenous compound that cells transform into NAD, she could repair the broken network and rapidly restore communication and mitochondrial function. If the compound was given early enough—prior to excessive mutation accumulation—within days, some aspects of the aging [disease] process could be reversed."

Also important to note, "more than just an intrusive molecule that foils communication, HIF-1 normally switches on when the body is deprived of oxygen. Otherwise, it remains silent."

To me, these findings point the way toward earnest and future biomedical research.

@Cj, these are great findings.

Michael, my thoughts as well.