Processing of both early and late primary transcripts requires participation of splicing factors including SF2/ASF, an ubiquitous factor which plays a pivotal role in alternative and constitutive splicing of precursor mRNAs of mammalian cells [12], [13], [14], [15], [16].
Factors of other families, such as POU and bZIP are often involved in regulation of basic cell cycle machinery; e.g. POU2F1 is an ubiquitous factor involved in stimulation of replication [ 27] and also participates in early mouse embryogenesis [ 28].
This transcription factor is a ubiquitous component of enhancer-associated protein assemblies.
This stretch of DNA includes the so-called 'Ret4' element which consists of a single low-affinity Crx site as well as a binding site for an unidentified ubiquitous factor [45].
This Rho minimal basal promoter includes the so-called 'Ret4' element which contains a single low affinity Crx site (log odds score = 5.1) and a binding site for an unidentified ubiquitous factor [45].
NF-kB (nuclear factor kappa B) is a ubiquitous transcription factor that is formed by two subunits of Rel family, which include seven members, p65 (RelA), p50 (NF-kB1), c-Rel, RelB, p100, p105, p52 [ 56].
The GAGA factor (GAF) of Drosophila is a ubiquitous transcription factor that plays important roles in multiple processes ranging from regulation of gene expression to the structural organization of heterochromatin and chromatin remodeling [ 1- 5].
Another pivotal oxygen sensor is the master regulator of the hypoxic response, namely hypoxia-inducible factor 1 α (HIF1 α), a ubiquitous transcription factor that is kept, under normoxia, at often undetectable protein level by continuous degradation via the 26S proteasome.
