There are certain mRNA that aren't suppose to be translated by other ribosomes, right?

[Genecks]

My previous knowledge of genetics is a little foggy, but I remember there being something about one type of ribosome not being able to (EDIT: ribosomes translate; RNA polymerase transcribes) translate the mRNA from another organism. I think it was that prokaryotic ribosomes can't translate eukaryotic mRNA. Or maybe it was the other way around?

 

Either way, I'm reading about the possible transcription of certain genes, such as the germ cell-less (gcl) gene inside of eukaryotic cells during development. It would appear that the hypothesis is that the mitochondrial ribosomes help at translating this gene.

 

How could this be?

 

I suspect the following:

 

1. Somehow the gcl gene is deeply rooted in prokaryotic genetics

2. the amino acid sequences of the mitochondrial ribosomes are much different that the binding principles are different (how mRNA attaches to the ribosome and goes about translation)

Edited September 19, 2010 by Genecks

[Darwinsbulldog]

My previous knowledge of genetics is a little foggy, but I remember there being something about one type of ribosome not being able to transcribe the mRNA from another organism. I think it was that prokaryotic ribosomes can't transcribe eukaryotic mRNA. Or maybe it was the other way around?

 

Either way, I'm reading about the possible transcription of certain genes, such as the germ cell-less (gcl) gene inside of eukaryotic cells during development. It would appear that the hypothesis is that the mitochondrial ribosomes help at transcribing this gene.

 

How could this be?

 

I suspect the following:

 

1. Somehow the gcl gene is deeply rooted in prokaryotic genetics

2. the amino acid sequences of the mitochondrial ribosomes are much different that the binding principles are different (how mRNA attaches to the ribosome and goes about transcription)

If the gene is close enough, then you can use a gene from species X to "rescue" the "same" gene in species Y, even though there may be great genetic distance between the two species. Experiment shave knocked out a fruit fly gene, and rescued it with the equivalent human gene. So presumably, becuase the rescue of function works, then the human gene is being expressed in the fly. That surely implies that the info from the human gene gets put into the 'fly" mRNA, and goes to the fly ribosome, and the human protein pops out at the other end of the assembly line.Genes are just software. So long as the organism is "IBM-compatible" , the program will run.

Edited September 14, 2010 by Darwinsbulldog

[Mr Skeptic]

RNA is dangerous and is quickly degraded by cells, especially if it is missing its cap.

 

http://en.wikipedia.org/wiki/Mrna#Degradation

[CharonY]

First of all ribosomes translate and do not transcribe.The initiation of translation is different in pro- and eukaryotes. Most notably the ribosome binding sequence on the mRNA is different. The famous Shine-Dalgarno and Kozak sequences, respectively. This is important basics (if it does not tell you anything, grab a textbook now, also ).

 

Regarding gcl the last time I heard about it was already a few years back, but from what I recall the evidence was not fully on the side of translation by mitochondrial ribosomes. I remember basically two explanations. A) presence of cis regulatory sequences that allow the translation, or in fact translation by cytoplasmic mitochondria.

[Genecks]

If the gene is close enough, then you can use a gene from species X to "rescue" the "same" gene in species Y, even though there may be great genetic distance between the two species....

 

Yes, but there is a difference between prokaryotes and eukaryotes. The way the mRNA gene binds to the ribosome is different. I am under the assumption that the mitochondria, in this situation, are largely under the influence of prokaryotic evolution.

 

First of all ribosomes translate and do not transcribe.The initiation of translation is different in pro- and eukaryotes. Most notably the ribosome binding sequence on the mRNA is different. The famous Shine-Dalgarno and Kozak sequences, respectively. This is important basics (if it does not tell you anything, grab a textbook now, also ).

 

Regarding gcl the last time I heard about it was already a few years back, but from what I recall the evidence was not fully on the side of translation by mitochondrial ribosomes. I remember basically two explanations. A) presence of cis regulatory sequences that allow the translation, or in fact translation by cytoplasmic mitochondria.

 

So, would you say that the counterargument is that the gcl gene does have that Kozak sequence? I'm not sure if the gcl gene has been sequenced. But obviously a sequence should have the information describing whether or not the sequence possesses the ability bind to eukaryotic or prokaryotic ribosomes, right?

 

An extreme exception would be that the ribosomes produced by the particular neighboring mitochondria are very different from other mitochondria.

 

I'm just curious about this situation, so it's so close to "home," the beginning stages of development in a multicellular eukaryotic organism. Maybe it was a sign of some missing link between single-cell to multicellular development.

 

And are you saying in this part "...or in fact translation by cytoplasmic mitochondria." that may indeed be translated by mitochondria?

 

p.s.

 

Thanks. Post was changed and edited.

Edited September 19, 2010 by Genecks

[CharonY]

1) regulatory sequences are outside the coding sequence. Each mRNA is preceded by a an untranslated region and is generally followed by another one. Thus knowing the gene sequence does not provide information on the initiation complex.

 

2) The Kozak sequence is the consensus binding site for the eukaryotic ribsome complex.

 

3) I mistyped I meant cytoplasmic ribosomes, of course, not mitochondria. Sorry for the confusion.