The transcription factors Sp1 and Oct-1 interact physically to regulate human U2 snRNA gene expression

Ström, Anne-Christine; Forsberg, Maud; Lillhager, Peter; Westin, Gunnar

doi:10.1093/nar/24.11.1981

Cited by 79 publications

(48 citation statements)

References 39 publications

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“…This domain contains 52 glutamines interrupted mainly by histidines, resulting in a highly polar stretch suitable for interactions. Certainly, Q-rich domains are present in proteins with diverse roles in gene expression and serve as proteinprotein interaction and multimerisation modules (Pascal and Tjian 1991;Emili et al 1994;Stott et al 1995;Strom et al 1996). To test whether the Q-rich domain could confer translational repression, we deleted it from dUNR and fused it to hUNR.…”

Section: Discussionmentioning

confidence: 99%

Functional domains of Drosophila UNR in translational control

Abaza

Gebauer²

2008

RNA

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Translational repression of male-specific-lethal 2 (msl-2) mRNA by Sex-lethal (SXL) is an essential regulatory step of X chromosome dosage compensation in Drosophila. Translation inhibition requires that SXL recruits the protein upstream of N-ras (UNR) to the 39 UTR of msl-2 mRNA. UNR is a conserved, ubiquitous protein that contains five cold-shock domains (CSDs). Here, we dissect the domains of UNR required for translational repression and complex formation with SXL and msl-2 mRNA. Using gel-mobility shift assays, the domain involved in interactions with SXL and msl-2 was mapped specifically to the first CSD (CSD1). Indeed, excess of a peptide containing this domain derepressed msl-2 translation in vitro. The CSD1 of human UNR can also form a complex with SXL and msl-2. Comparative analyses of the CSDs of the Drosophila and human proteins together with site-directed mutagenesis experiments revealed that three exposed residues within CSD1 are required for complex formation. Tethering assays showed that CSD1 is not sufficient for translational repression, indicating that UNR binding to SXL and msl-2 can be distinguished from translation inhibition. Repression by tethered UNR requires residues from both the aminoterminal Q-rich stretch and the two first CSDs, indicating that the translational effector domain of UNR resides within the first 397 amino acids of the protein. Our results identify domains and residues required for UNR function in translational control.

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Section: Discussionmentioning

confidence: 99%

Functional domains of Drosophila UNR in translational control

Abaza

Gebauer²

2008

RNA

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“…Studies have indicated that these elements enhance DNA replication and have identified Sp1 sites as important components (39,40). Because Oct-1 and Sp1 can physically interact (41), it is possible that Oct-1 contributes to the Sp1-dependent stimulation. However, this model is unlikely to account for the striking requirement for Oct-1 at this stage of infection, because the IE elements have only a minor stimulatory effect on DNA replication.…”

Section: Discussionmentioning

confidence: 99%

Herpes simplex virus infections are arrested in Oct-1-deficient cells

Nogueira

Wang

Tantin

et al. 2004

Proc. Natl. Acad. Sci. U.S.A.

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Expression of the herpes simplex virus (HSV) immediate early (IE)genes is regulated by a multiprotein complex that is assembled on the TAATGARAT enhancer core element. The complex contains the cellular POU domain protein Oct-1, the viral transactivator VP16, and the cellular cofactor host cell factor 1. The current model suggests that the assembly depends on recognition of the core element by Oct-1. Here, HSV infection of Oct-1-deficient mouse embryonic fibroblast cells demonstrates that Oct-1 is critical for IE gene expression at low multiplicities of infection (moi). However, the protein is not essential for IE gene expression at high moi, indicating that VP16-mediated transcriptional induction through other IE regulatory elements is also important. This induction depends, at least in part, on the GA-binding protein binding elements that are present in each IE enhancer domain. Surprisingly, whereas the viral IE genes are expressed after high moi infection of Oct-1-deficient cells, the assembly of viral replication factories is severely impaired, revealing a second critical role for Oct-1 in HSV replication. The results have implications for both the HSV lytic and latency-reactivation cycles.

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“…[5][6][7] Q-rich domains have been shown to be involved in the interaction between Sp1 and different classes of nuclear proteins, such as TATA-binding protein associated factors (TAFs), which are components of the general transcription factor TFIID. [8][9][10][11][12] The interaction between Sp1 and TAF4 via each Q-rich domain is considered to recruit RNA polymerase II to the transcription initiation site and activate transcription.…”

Section: Introductionmentioning

confidence: 99%

Interaction between isolated transcriptional activation domains of Sp1 revealed by heteronuclear magnetic resonance

et al. 2012

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The promoter-specific transcription factor Sp1 is expressed ubiquitously, and plays a primary role in the regulation of the expression of many genes. Domains A and B located in the N-terminal half of the protein are characterized by glutamine-rich (Q-rich) sequences. These Q-rich domains have been shown to be involved in the interaction between Sp1 and different classes of nuclear proteins, such as TATA-binding protein associated factors. Furthermore, the selfassociation of Sp1 via Q-rich domains is also important for the regulation of transcriptional activity. It has been considered that an Sp1 molecule bound to a ''distal'' GC-box synergistically interacts with another Sp1 molecule at a ''proximal'' binding site. Although the formation of multimers via Q-rich domains seems functionally important for Sp1, little is known about the structural and physicochemical nature of the interaction between Q-rich domains. We analyzed the structural details of isolated glutamine-rich B (QB) domains of Sp1 by circular dichroism (CD), analytical ultracentrifugation, and heteronuclear magnetic resonance spectroscopy (NMR). We found the isolated QB domains to be disordered under all conditions examined. Nevertheless, a detailed analysis of NMR spectra clearly indicated interaction between the domains. In particular, the C-terminal half was responsible for the self-association. Furthermore, analytical ultracentrifugation demonstrated weak but significant interaction between isolated QB domains. The self-association between QB domains would be responsible, at least in part, for the formation of multimers by full-length Sp1 molecules that has been proposed to occur during transcriptional activation.

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The transcription factors Sp1 and Oct-1 interact physically to regulate human U2 snRNA gene expression

Cited by 79 publications

References 39 publications

Functional domains of Drosophila UNR in translational control

Functional domains of Drosophila UNR in translational control

Herpes simplex virus infections are arrested in Oct-1-deficient cells

Interaction between isolated transcriptional activation domains of Sp1 revealed by heteronuclear magnetic resonance

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