RNA interference (RNAi)
The available genetic material in an individual or a species is one thing. All cells in the body have the same DNA. Forget that! (no, not really) That’s not the fun part. The fun part is how the genome works, and how genes are expressed, if at all. This is what actually keeps life ticking the way it does. This is why we have cells that look different and act differently. This is why your environment and choices can make a difference.
Transcriptional factors are molecules which can bind DNA and thus initiate transcription. Most of the time these are inactive in the cytoplasm because they have an inhibitor attached to them.
Hormones like oestrogen which are crucial to immunity, bone development, female reproduction, etc. can bind to transcriptional factors and release their inhibitor. Oestrogen crosses the plasma membrane freely as it is lipid-soluble.
This enables the transcriptional factor to migrate from the cytoplasm into the nucleus via the nuclear pore, bind DNA and initiate transcription of specific genes.
In eukaryotes, genes contain non-coding sequences which must be removed before mRNA is used to produce proteins. These are called introns as opposed to exons which are coding sequences. Splicing therefore is the process of excising (cutting out) introns to be left….