Second, some eukaryotic factors may not express or fold efficiently in the bacterial system, attributed to differing regulatory networks and transcriptional machinery.

This means the transcriptional machinery (RNA polymerase, transcription factors, etc.) cannot get at the gene.

In fact, the Cdk7 subunit of vertebrate CAK phosphorylates several components of the transcriptional machinery.

Regulates the nuclear accumulation of SMADS and has a key role in coupling them to the transcriptional machinery such as the mediator complex.

Unpackaged or loose chromatin is more transcriptionally active than tightly packaged chromatin because it is more accessible to transcriptional machinery.

Under a loose chromatin state, DNA is more accessible to transcriptional machinery and thus expression is activated.

The first system they used is human red blood cells, which lack a nucleus, so they have no transcriptional machinery or even genes to transcribe.

Coactivators can then bind to the receptor complex, which may help to loosen the chromatin structure from the histones or may interact with the transcriptional machinery.

The assembled enhanceosome recruits transcriptional machinery such as RNA polymerase to the promoter region to initiate gene expression.

There are some other transcription factors that compete for some of the components of the transcriptional machinery for the activation of Nodal target genes.