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Dual functions of TAF7L in adipocyte differentiation.

Zhou H, Kaplan T, Li Y, Grubisic I, Zhang Z, Wang PJ, Eisen MB, Tjian R - Elife (2013)

Bottom Line: Depletion of TAF7L reduced adipocyte-specific gene expression, compromised adipocyte differentiation, and WAT development as well.Genome-wide mRNA-seq expression profiling and ChIP-seq binding studies confirmed that TAF7L is required for activating adipocyte-specific genes via a dual mechanism wherein it interacts with PPARγ at enhancers and TBP/Pol II at core promoters.In vitro binding studies confirmed that TAF7L forms complexes with both TBP and PPARγ.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular and Cell Biology , Howard Hughes Medical Institute, University of California, Berkeley , Berkeley , United States ; Li Ka Shing Center For Biomedical and Health Sciences, CIRM Center of Excellence, University of California, Berkeley , Berkeley , United States.

ABSTRACT
The diverse transcriptional mechanisms governing cellular differentiation and development of mammalian tissue remains poorly understood. Here we report that TAF7L, a paralogue of TFIID subunit TAF7, is enriched in adipocytes and white fat tissue (WAT) in mouse. Depletion of TAF7L reduced adipocyte-specific gene expression, compromised adipocyte differentiation, and WAT development as well. Ectopic expression of TAF7L in myoblasts reprograms these muscle precursors into adipocytes upon induction. Genome-wide mRNA-seq expression profiling and ChIP-seq binding studies confirmed that TAF7L is required for activating adipocyte-specific genes via a dual mechanism wherein it interacts with PPARγ at enhancers and TBP/Pol II at core promoters. In vitro binding studies confirmed that TAF7L forms complexes with both TBP and PPARγ. These findings suggest that TAF7L plays an integral role in adipocyte gene expression by targeting enhancers as a cofactor for PPARγ and promoters as a component of the core transcriptional machinery.DOI:http://dx.doi.org/10.7554/eLife.00170.001.

No MeSH data available.


Related in: MedlinePlus

TAF7L is enriched in 3T3-L1 differentiated adipocytes.(A) Expression of Taf7l and TFIID subunits prior to and 7 days (7D) post adipogenic induction of 3T3-L1 cells as shown by RT-qPCR analysis (A) and by Western blot (C). (B) Gene expression of adipocyte marker genes Adipsin, Adipoq and Fabp4 of 3T3-L1 adipocytes prior to and 7 days post adipogenic induction. mRNA levels in 3T3-L1 cells were assigned to 1, mRNA levels of each gene in 3T3-L1 adipocytes were compared to 3T3-L1 cells, data is mean from triplicates.DOI:http://dx.doi.org/10.7554/eLife.00170.004
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fig1s1: TAF7L is enriched in 3T3-L1 differentiated adipocytes.(A) Expression of Taf7l and TFIID subunits prior to and 7 days (7D) post adipogenic induction of 3T3-L1 cells as shown by RT-qPCR analysis (A) and by Western blot (C). (B) Gene expression of adipocyte marker genes Adipsin, Adipoq and Fabp4 of 3T3-L1 adipocytes prior to and 7 days post adipogenic induction. mRNA levels in 3T3-L1 cells were assigned to 1, mRNA levels of each gene in 3T3-L1 adipocytes were compared to 3T3-L1 cells, data is mean from triplicates.DOI:http://dx.doi.org/10.7554/eLife.00170.004

Mentions: To explore the regulatory mechanisms directing adipocyte formation and function, we asked whether there were significant changes to the core promoter recognition components during adipogenesis similar to what had been observed during myogenesis (Deato and Tjian, 2007). In particular, we set out to determine whether and which TAF subunits of the prototypic core promoter recognition complex TFIID increase or decrease in expression during adipocyte differentiation. Consistent with the previous observations from 3T3-L1 adipogenesis studies (Guermah et al., 2003), our analysis of both protein and mRNA levels revealed that TBP and most of the canonical subunits of TFIID are down-regulated during C3H10T1/2 differentiation (Figure 1A,B). Surprisingly however, one subunit (TAF7L) previously reported to be a component of TFIID primarily in testis (Pointud et al., 2003; Cheng et al., 2007) was found to be significantly up-regulated in differentiated C3H10T1/2 adipocytes (Figure 1A,B and Figure 1—figure supplement 2A) and 3T3-L1 adipocytes (Figure 1—figure supplement 1A,C). Importantly, this enrichment appears specific for the adipogenesis process since the mRNA abundance of Taf7l is downregulated to levels comparable to those of other TAF subunits during myogenesis (Figure 1C). To exclude the possibility that Taf7l enrichment reflects a cell culture artifact of C3H10T1/2 adipogenesis, we compared Taf7l mRNA and protein levels in bona fide mouse tissue. In concordance with previous studies, Taf7l is most highly expressed in testis (Pointud et al., 2003) (Figure 1D,E). Importantly, Taf7l also shows significant expression in WAT and detectable expression in liver, spleen, brown adipose tissue (BAT) and kidney, but not in muscle or brain tissue (Figure 1D,E). By contrast, the expression of canonical TFIID subunits such as TAF4 is low in both WAT and muscle as expected (Figure 1E). Taken together, these data indicate that TAF7L is indeed enriched in differentiated C3H10T1/2 and 3T3-L1 adipocytes and bona fide WAT.10.7554/eLife.00170.003Figure 1.TAF7L is enriched in terminally differentiated adipocytes and bona fide WAT.


Dual functions of TAF7L in adipocyte differentiation.

Zhou H, Kaplan T, Li Y, Grubisic I, Zhang Z, Wang PJ, Eisen MB, Tjian R - Elife (2013)

TAF7L is enriched in 3T3-L1 differentiated adipocytes.(A) Expression of Taf7l and TFIID subunits prior to and 7 days (7D) post adipogenic induction of 3T3-L1 cells as shown by RT-qPCR analysis (A) and by Western blot (C). (B) Gene expression of adipocyte marker genes Adipsin, Adipoq and Fabp4 of 3T3-L1 adipocytes prior to and 7 days post adipogenic induction. mRNA levels in 3T3-L1 cells were assigned to 1, mRNA levels of each gene in 3T3-L1 adipocytes were compared to 3T3-L1 cells, data is mean from triplicates.DOI:http://dx.doi.org/10.7554/eLife.00170.004
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Related In: Results  -  Collection

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fig1s1: TAF7L is enriched in 3T3-L1 differentiated adipocytes.(A) Expression of Taf7l and TFIID subunits prior to and 7 days (7D) post adipogenic induction of 3T3-L1 cells as shown by RT-qPCR analysis (A) and by Western blot (C). (B) Gene expression of adipocyte marker genes Adipsin, Adipoq and Fabp4 of 3T3-L1 adipocytes prior to and 7 days post adipogenic induction. mRNA levels in 3T3-L1 cells were assigned to 1, mRNA levels of each gene in 3T3-L1 adipocytes were compared to 3T3-L1 cells, data is mean from triplicates.DOI:http://dx.doi.org/10.7554/eLife.00170.004
Mentions: To explore the regulatory mechanisms directing adipocyte formation and function, we asked whether there were significant changes to the core promoter recognition components during adipogenesis similar to what had been observed during myogenesis (Deato and Tjian, 2007). In particular, we set out to determine whether and which TAF subunits of the prototypic core promoter recognition complex TFIID increase or decrease in expression during adipocyte differentiation. Consistent with the previous observations from 3T3-L1 adipogenesis studies (Guermah et al., 2003), our analysis of both protein and mRNA levels revealed that TBP and most of the canonical subunits of TFIID are down-regulated during C3H10T1/2 differentiation (Figure 1A,B). Surprisingly however, one subunit (TAF7L) previously reported to be a component of TFIID primarily in testis (Pointud et al., 2003; Cheng et al., 2007) was found to be significantly up-regulated in differentiated C3H10T1/2 adipocytes (Figure 1A,B and Figure 1—figure supplement 2A) and 3T3-L1 adipocytes (Figure 1—figure supplement 1A,C). Importantly, this enrichment appears specific for the adipogenesis process since the mRNA abundance of Taf7l is downregulated to levels comparable to those of other TAF subunits during myogenesis (Figure 1C). To exclude the possibility that Taf7l enrichment reflects a cell culture artifact of C3H10T1/2 adipogenesis, we compared Taf7l mRNA and protein levels in bona fide mouse tissue. In concordance with previous studies, Taf7l is most highly expressed in testis (Pointud et al., 2003) (Figure 1D,E). Importantly, Taf7l also shows significant expression in WAT and detectable expression in liver, spleen, brown adipose tissue (BAT) and kidney, but not in muscle or brain tissue (Figure 1D,E). By contrast, the expression of canonical TFIID subunits such as TAF4 is low in both WAT and muscle as expected (Figure 1E). Taken together, these data indicate that TAF7L is indeed enriched in differentiated C3H10T1/2 and 3T3-L1 adipocytes and bona fide WAT.10.7554/eLife.00170.003Figure 1.TAF7L is enriched in terminally differentiated adipocytes and bona fide WAT.

Bottom Line: Depletion of TAF7L reduced adipocyte-specific gene expression, compromised adipocyte differentiation, and WAT development as well.Genome-wide mRNA-seq expression profiling and ChIP-seq binding studies confirmed that TAF7L is required for activating adipocyte-specific genes via a dual mechanism wherein it interacts with PPARγ at enhancers and TBP/Pol II at core promoters.In vitro binding studies confirmed that TAF7L forms complexes with both TBP and PPARγ.

View Article: PubMed Central - PubMed

Affiliation: Department of Molecular and Cell Biology , Howard Hughes Medical Institute, University of California, Berkeley , Berkeley , United States ; Li Ka Shing Center For Biomedical and Health Sciences, CIRM Center of Excellence, University of California, Berkeley , Berkeley , United States.

ABSTRACT
The diverse transcriptional mechanisms governing cellular differentiation and development of mammalian tissue remains poorly understood. Here we report that TAF7L, a paralogue of TFIID subunit TAF7, is enriched in adipocytes and white fat tissue (WAT) in mouse. Depletion of TAF7L reduced adipocyte-specific gene expression, compromised adipocyte differentiation, and WAT development as well. Ectopic expression of TAF7L in myoblasts reprograms these muscle precursors into adipocytes upon induction. Genome-wide mRNA-seq expression profiling and ChIP-seq binding studies confirmed that TAF7L is required for activating adipocyte-specific genes via a dual mechanism wherein it interacts with PPARγ at enhancers and TBP/Pol II at core promoters. In vitro binding studies confirmed that TAF7L forms complexes with both TBP and PPARγ. These findings suggest that TAF7L plays an integral role in adipocyte gene expression by targeting enhancers as a cofactor for PPARγ and promoters as a component of the core transcriptional machinery.DOI:http://dx.doi.org/10.7554/eLife.00170.001.

No MeSH data available.


Related in: MedlinePlus