Transcription Negative regulation

Srinivasan P, Marie M. Signal transducer and activator of transcription negatively regulates constitutive gamma interferon-inducible lysosomal thiol reductase expression. Immunology. 2011 132 209-16. 

It should be noted that the NRE defined in these experiments is distinct from the previously described c-mos UMS sequence (Blair et al., 1984 Wood et al., 1984). The UMS is located approximately 1.4 kb upstream of the c-mos spermatocyte promoter and was identified because it blocked activation of c-mos transforming potential by insertion of retroviral promoters. It is thought to act as a transcriptional terminator, blocking transcription of c-mos initiated at upstream sequences. However, both the spermatocyte and oocyte transcription initiation sites are substantially downstream of the UMS. Moreover, the presence or absence of the UMS does not affect c-mos expression in either microin-jected oocytes (Pal et al., 1991) or transfected NIH 3T3 cells (Zinkel et al., 1992). It thus appears unlikely that the UMS functions as a negative regulator of c-mos transcription from either the spermatocyte or oocyte promoters in somatic cells. 

Negative regulators (repressors) Turn off transcription when a specific effector protein binds to a specific repressor sequence in the DNA. 

Mirnezami, a. H., et ah, Hdm2 recruits a hypoxia-sensitive corepressor to negatively regulate p5 3-dependent transcription. Curr Biol, 2003, 13(14), 1234-9. 

Acetylation of p53, E2F and many other proteins not only activates their transcriptional activities but also half-life (Li et al, 2002 Martlnez-Balbas et al, 2000). Apart from DNA binding, and protein half-life, acetylation also plays pivotal role in protein-protein interactions thereby cellular processes involved. However, the acetylation of pRb regulates the specific interaction with E2F-1 (Markham et al, 2006). E2F activity is negatively regulated by its interaction with pRb, which recruits histone decetylase complexes and probably lead to the deacetylation of E2F. 

Barber CM et al., report that histone H2A is highly phosphorylated at Serine 1 residues during mitosis in the worm, fly, and mammalian cells (Barber et al, 2004). This phosphorylation by MSKl negatively regulated transcription on chromatin templates (Zhang et al, 2004). 

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