How many levels of gene control exists?

[Eagle9]

We know that some genes produce mRNAs (and then proteins) and some other genes produces just ncRNAs (non-coding RNA) that play regulatory roles (yes, I know that some ncRNAs play other roles, but let’s forget about them now).

I want to know a bit more about this regulatory processes. Does every such certain gene produce one ncRNA that controls one other certain gene? Or maybe there is much more complex situation? For instance, can one gene produce ncRNA that controls other gene (How many, one? or maybe more?) producing other regulatory ncRNA(s) that from its side controls other gene and so on?

This actually can make a very complex interlacement/interlacement/labyrinth, something like this:

So, what can you tell me about this question?

 

[Ygggdrasil]

The question is very broad given the variety of ncRNAs present in the cell. Here are some general answers to your questions:
1. There are examples where one particular locus in the genome produces one ncRNA, and there are examples of loci that produce multiple ncRNAs.
2. There are some ncRNAs that largely regulate the activity of one gene, and there are ncRNAs that regulate the activity of multiple genes (e.g. the XIST RNA is involved in regulating the activity of an entire chromosome).
3. miRNAs (micro RNAs) are another example with complex regulation. miRNAs bind to mRNAs (messenger RNAs) to post-transcriptionally regulate their translation. One miRNA can regulate the activity of multiple different mRNAs and one mRNA can be regulated by multiple different types of miRNAs.
4. There are definitely cases where there are different levels of control. For example, consider a miRNA that regulates the translation of a transcription factor.

Teasing out the huge complexity of the huge web of genetic interactions that regulate gene expression (for example, see Fig 1 in http://www.sciencemag.org/content/327/5964/425.full) is a major current area of research, which the field of systems biology is focused on studying.

 

[Eagle9]

There are definitely cases where there are different levels of control. For example, consider a miRNA that regulates the translation of a transcription factor.

Well, here are two levels only; can there be more (4, 5 or even more) levels?

 

[Ygggdrasil]

Well, here are two levels only; can there be more (4, 5 or even more) levels?

Almost certainly.