Question

1) The FOXP2 transcription factor is expressed in human brain, heart, and lungs. The protein is required for normal development. Given that eukaryotic genes do not occur in operons, how can the STAT 1 transcription factor simultaneously regulate the transcription of more than 275 different target genes?

2) Many genes are transcribed constitutively, while others are regulated specifically. Regulation can occur in response to various stimuli in either a positive or negative direction. Describe one type of gene that would be constitutively expressed and one type of gene that would be regulated.

3) Continuing on the question above, describe why having both positive and negative regulation can be beneficial to a cell.

Answer 1

1. STAT proteins are actvated by phosphorylation which is mediated by receptor associated kinases. as a result of this it dimerize and form homo or heterodimers. Then it it is translocated to nucleus and acts as transcription factors. STAT are activated by many ligands , for eg, Interferon alpha, interferon gamma, interleukin 6 platelet derived growth factor, epidermal growth factor,etc. Due to this versatility , STAT can regulate so many genes.

2. The genes which codes for glycolysis or Krebs cycle are constitutively expressed as the products of these genes are required all the time as long as the organism is alive. On the other hand, the genes which are responsible for metabolism of some specific compounds are only expressed when that specific compound metabolism is required. When metabolism of that compound is nit required, the genes remained turned off and induced as soon as the specific compound arrives.

According to CHEGG guideline I have answered first question i.e. question no 1 and also an extra question i.e question no 2. Please post each question separately. Thank you.