MLE Functions as a Transcriptional Regulator of the roX2 Gene

Lee, Chee-Gun; Reichman, Trevor; Baik, Tina; Mathews, Michael B.

doi:10.1074/jbc.m408207200

Cited by 21 publications

(17 citation statements)

References 37 publications

(19 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…As shown in Fig. S1A and Table S1, we identified several RNA helicase proteins, and RHA in particular caught our attention because it is a well-known transcriptional activator (22) and its Drosophila homolog MLE has been shown to bind to the ATRS-containing sequence of rox2 gene promoter (26). Thus, we hypothesized that RHA is a DNA-binding partner for EGFR-mediated gene transcription in the nucleus.…”

Section: Resultsmentioning

confidence: 99%

“…RHA regulates gene transcription by interacting with transcription factors (22) or by binding directly to the target gene promoter (25). Moreover, Drosophila MLE activates rox2 transcription by binding to an ATrich region of the gene promoter (26). Interestingly, this AT-rich region contains the previously reported EGFR-binding sequence, an ATRS in the promoter regions of cyclin D1 (17) and inducible NOS (iNOS) (13), raising the very interesting question of whether RHA serves as a DNA-binding partner for nuclear EGFR to activate gene transcription.…”

mentioning

confidence: 99%

See 1 more Smart Citation

RNA helicase A is a DNA-binding partner for EGFR-mediated transcriptional activation in the nucleus

Huo

Wang

Xia

et al. 2010

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

View full text Add to dashboard Cite

EGF induces the translocation of EGF receptor (EGFR) from the cell surface to the nucleus where EGFR activates gene transcription through its binding to an AT-rich sequence (ATRS) of the target gene promoter. However, how EGFR, without a DNA-binding domain, can bind to the gene promoter is unclear. In the present study, we show that RNA helicase A (RHA) is an important mediator for EGFRinduced gene transactivation. EGF stimulates the interaction of EGFR with RHA in the nucleus of cancer cells. The EGFR/RHA complex then associates with the target gene promoter through binding of RHA to the ATRS of the target gene promoter to activate its transcription. Knockdown of RHA expression in cancer cells abrogates the binding of EGFR to the target gene promoter, thereby reducing EGF/EGFR-induced gene expression. In addition, interruption of EGFR-RHA interaction decreases the EGFR-induced promoter activity. Consistently, we observed a positive correlation of the nuclear expression of EGFR, RHA, and cyclin D1 in human breast cancer samples. These results indicate that RHA is a DNA-binding partner for EGFR-mediated transcriptional activation in the nucleus.cyclin D1 | nuclear translocation | inducible nitric oxide synthase | transcription C ell surface EGF receptor (EGFR) has been shown to be localized in the nucleus (1-4). Nuclear EGFR has been demonstrated to contribute to cancer cell resistance to cetuximab and radiation treatment (5, 6) and to be negatively correlated with overall survival of patients with multiple cancer types (7-11). Moreover, nuclear EGFR interacts with signal transducer and activator of transcription 3 (STAT3), signal transducer and activator of transcription 5A (STAT5A), E2F1, DNA-dependent protein kinase (DNA-PK), and proliferating cell nuclear antigen (PCNA) and plays important roles in cell transformation, proliferation, and DNA repair and replication (12-16). Nuclear EGFR regulates gene expression by binding to an AT-rich sequence (ATRS) of the gene's promoter (13,16,17). Additionally, a recent unbiased protein-DNA interactome study indicates that EGFR is a DNAbinding protein (18). However, EGFR does not contain a DNAbinding domain, and evidence supporting direct binding of EGFR to the specific DNA sequence is lacking. Thus, identifying the DNA-binding partner for EGFR is crucial for understanding how EGFR regulates gene transcription in the nucleus.RNA helicase A (RHA), the human homolog of Drosophila maleless (MLE) that increases the transcription of male X-linked genes (19), is a multifunctional protein and is conserved in Drosophila and mammals (20)(21)(22). RHA belongs to the aspartateglutamate-alanine-aspartate (DEAD) box family of proteins and has the ability to bind to RNA and DNA (23,24). RHA regulates gene transcription by interacting with transcription factors (22) or by binding directly to the target gene promoter (25). Moreover, Drosophila MLE activates rox2 transcription by binding to an ATrich region of the gene promoter (26). Interestingly, this AT-rich region contains the previo...

show abstract

Section: Resultsmentioning

confidence: 99%

mentioning

confidence: 99%

RNA helicase A is a DNA-binding partner for EGFR-mediated transcriptional activation in the nucleus

Huo

Wang

Xia

et al. 2010

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

View full text Add to dashboard Cite

show abstract

“…MLE is required for the stabilization of roX1 RNA in early embryos (20) and has been implicated in the transcription regulation of the roX2 gene (15). These published observations led us to ask whether the lack of spreading by complexes that included either of the two helicase-deficient MLE proteins was caused by misregulation of the levels of roX RNAs.…”

Section: Resultsmentioning

confidence: 99%

The MLE Subunit of the Drosophila MSL Complex Uses Its ATPase Activity for Dosage Compensation and Its Helicase Activity for Targeting

Morra¹,

Smith²,

Yokoyama³

et al. 2008

Molecular and Cellular Biology

View full text Add to dashboard Cite

In Drosophila, dosage compensation-the equalization of most X-linked gene products between XY males and XX females-is mediated by the MSL complex that preferentially associates with numerous sites on the X chromosome in somatic cells of males, but not of females. The complex consists of a noncoding RNA and a core of five protein subunits that includes a histone acetyltransferase (MOF) and an ATP-dependent DEXH box RNA/DNA helicase (MLE). Both of these enzymatic activities are necessary for the spreading of the complex to its sites of action along the X chromosome. MLE is related to the ATPases present in complexes that remodel chromatin by altering the positioning or the architectural relationship between nucleosomes and DNA. In contrast to MLE, none of these enzymatic subunits has been shown to possess double-stranded nucleic acid-unwinding activity. We investigated the function of MLE in the process of dosage compensation by generating mutations that separate ATPase activity from duplex unwinding. We show that the ATPase activity is sufficient for MLE's role in transcriptional enhancement, while the helicase activity is necessary for the spreading of the complex along the X chromosome.It is widely recognized that the association of DNA, histones, and nonhistone proteins in chromatin leads to a compacted structure that is unfavorable to transcription. This association must be modified in order to allow the transcriptional machinery to access the promoter regions of genes and to carry out RNA synthesis. There are two general means by which such modifications can be achieved: the ATP-dependent remodeling of the DNA-nucleosome association and the covalent modification of histones. Large multiprotein complexes use the ATPase activity of one of their subunits to slide nucleosomes along the DNA molecule or to alter the torsional stress of the DNA as it wraps around nucleosomes. Other complexes bring histone acetyltransferases, methylases, kinases, or ubiquitinases to the nucleosomes in order to modify specific residues, predominantly but not exclusively in the free N-terminal tails. These modifications alter the charge difference between the histone and DNA molecules, reducing their affinity for one another, or serve as signals for the docking of transcription activators and coactivators (reviewed in references 13, 16, and 29). The MSL complex of Drosophila consists of a core of five protein subunits (encoded by male-specific lethal 1, 2, and 3 [msl1, msl2, and msl3], males absent on the first [mof], and maleless [mle]), as well as one of two noncoding RNAs (RNA on the X1 and X2 [roX1 and roX2]). The complex preferentially associates with numerous sites on the X chromosome in somatic cells of males, but not of females. It is responsible for an enhancement of the transcriptional rates of a substantial number of X-linked genes, thereby mediating a compensatory effect for the difference in the dosages of these genes between males and females. The presence of the MSL complex on the male X chromosome is correlated with a ...

show abstract

“…MOF and MLE, as well as MSL3, require RNA for their localization to the X chromosome, and in turn, the roX RNAs are stabilized by the localization of the MSL complex to the X chromosome (2,8,40,46). In addition, transcription of roX RNAs is controlled by the MSL proteins (4,34,45). Together, these data uncover a series of interactions between components of the MSL complex that are required to ensure the complex's correct localization and activity.…”

mentioning

confidence: 80%

Zinc Finger Protein Zn72D Promotes Productive Splicing of the maleless Transcript

Worringer

Panning

2007

Molecular and Cellular Biology

View full text Add to dashboard Cite

In organisms with sex chromosomes, dosage compensation equalizes gene expression between the sexes. In Drosophila melanogaster males, the male-specific lethal (MSL) complex of proteins and two noncoding roX RNAs coat the X chromosome, resulting in a twofold transcriptional upregulation to equalize gene expression with that of females. How MSL complex enrichment on the X chromosome is regulated is not well understood. We performed an RNA interference screen to identify new factors required for dosage compensation. Using a Drosophila Schneider S2 cell line in which green fluorescent protein (GFP)-tagged MSL2 localizes to the X chromosome, we assayed ϳ7,200 knockdowns for their effects on GFP-MSL2 distribution. One factor identified is the zinc finger protein Zn72D. In its absence, the MSL complex no longer coats the X chromosome. We demonstrate that Zn72D is required for productive splicing of the transcript for the MSL protein Maleless, explaining the dosage compensation defect. However, Zn72D is required for the viability of both sexes, indicating its functions are not sex specific. Consistent with this, Zn72D colocalizes with elongating RNA polymerase II, implicating it as a more general factor involved in RNA metabolism.

show abstract

MLE Functions as a Transcriptional Regulator of the roX2 Gene

Cited by 21 publications

References 37 publications

RNA helicase A is a DNA-binding partner for EGFR-mediated transcriptional activation in the nucleus

RNA helicase A is a DNA-binding partner for EGFR-mediated transcriptional activation in the nucleus

The MLE Subunit of the Drosophila MSL Complex Uses Its ATPase Activity for Dosage Compensation and Its Helicase Activity for Targeting

Zinc Finger Protein Zn72D Promotes Productive Splicing of the maleless Transcript

Contact Info

Product

Resources

About