Inding motifs for SRY, an androgen receptor co-repressor [40]. SRY is a sex-determining gene on the Y chromosome, and mutations in this gene can cause abnormal sex development [41?3]. The regulation of MGARP by SRY, if validated, would suggest a pathway by which the androgen receptor modulates MGARP expression and in turn, MGARP may also mediate the biological and physiological effects of SRY. Together, our data suggest that the proximal promoter is Sp1-centered and the dependence of Sp1 for endogenous MGARP expression indicates that Sp1 is one major transactivator for the MGARP promoter, and additional regulatory factors may participate in regulation of the whole gene 1676428 promoter. In summary, we defined Sp1 as a major MGARP transactivator in the proximal MGARP promoter and identified two GC boxes in this region that mediate the transactivation of MGARP gene by Sp1. Sp1-driven transcription can be further enhanced by ERa, suggesting that the functional synergy between ER and Sp1 mediates the stimulating effect that estrogen was shown to have on MGARP transcription, providing a molecular mechanism for MGARP transcriptional regulation by steroids.Figure S2 Analysis of different truncated MGARP promoter activity by red fluorescent protein. (DOCX) Figure S3 Endogenous expression of MGARP in HEK293T cells and Y1 cells. (DOCX) Table S1 Primers for constructing different 
deletion reportervectors. (DOCX)Text S1 Bioinformatics analysis.(DOCX)Text S2 Western blot assay.(DOCX)AcknowledgmentsWe would like to express our appreciations to Dr. Samuel Shao-Min Zhang (Neural and Behavioral Sciences, Pennsylvania State University College of Medicine) for the constructive discussion about promoter analysis and Dr. Jonathan Horowitz (Department of Molecular Biomedical Sciences, North Carolina State University’s College of Veterinary Medicine, USA) for kindly providing us with the Sp1 expression plasmid. We would also thank Dr. Adam Sowalsky (BIDMC, Harvard Medical School, Boston, USA) for reading Hesperidin site through our manuscript.Author ContributionsConceived and designed the experiments: DJ SZ. Performed the experiments: DJ RL DM NL YW. Analyzed the data: DJ SC SZ. 
Contributed reagents/materials/analysis tools: SC. Wrote the paper: DJ SC SZ.Supporting InformationFigure S1 Detection of basal activity of the MGARP promoter by red fluorescence. (DOCX)
Homooligomeric proteins have large interface areas between the subunits resulting in stable complexes [1?]. Because the molecular functions of homooligomers often require their complete oligomeric forms, the overall structure of a homooligomer may help understand its molecular function [5,6]. It is known that the complex structure of a homooligomer often assumes a symmetric structure [7], with the subunits arranged in either a `close-packed’ (or dihedral) form or a `ring’ form [8]. The close-packed form has n/2-fold rotational symmetry around one rotational axis (designated as Dn where n is the number of subunits; axis 1 in Figure 1B) and 2-fold rotational symmetry around the other rotational axes (axes 2? in Figure 1B) perpendicular to the first rotational axis. Oligomers with this form contain an even number of subunits. In a statistical analysis of the Protein Data Bank (PDB) [9] (see Materials and Methods), we found that homooligomers composed of even numbers of subunits are dominant (Figure 1C) because of the abundance of 23115181 the closepacked oligomers. In the close-packed form, the subunit interfaces are arranged in a order BIBS39 face-t.Inding motifs for SRY, an androgen receptor co-repressor [40]. SRY is a sex-determining gene on the Y chromosome, and mutations in this gene can cause abnormal sex development [41?3]. The regulation of MGARP by SRY, if validated, would suggest a pathway by which the androgen receptor modulates MGARP expression and in turn, MGARP may also mediate the biological and physiological effects of SRY. Together, our data suggest that the proximal promoter is Sp1-centered and the dependence of Sp1 for endogenous MGARP expression indicates that Sp1 is one major transactivator for the MGARP promoter, and additional regulatory factors may participate in regulation of the whole gene 1676428 promoter. In summary, we defined Sp1 as a major MGARP transactivator in the proximal MGARP promoter and identified two GC boxes in this region that mediate the transactivation of MGARP gene by Sp1. Sp1-driven transcription can be further enhanced by ERa, suggesting that the functional synergy between ER and Sp1 mediates the stimulating effect that estrogen was shown to have on MGARP transcription, providing a molecular mechanism for MGARP transcriptional regulation by steroids.Figure S2 Analysis of different truncated MGARP promoter activity by red fluorescent protein. (DOCX) Figure S3 Endogenous expression of MGARP in HEK293T cells and Y1 cells. (DOCX) Table S1 Primers for constructing different deletion reportervectors. (DOCX)Text S1 Bioinformatics analysis.(DOCX)Text S2 Western blot assay.(DOCX)AcknowledgmentsWe would like to express our appreciations to Dr. Samuel Shao-Min Zhang (Neural and Behavioral Sciences, Pennsylvania State University College of Medicine) for the constructive discussion about promoter analysis and Dr. Jonathan Horowitz (Department of Molecular Biomedical Sciences, North Carolina State University’s College of Veterinary Medicine, USA) for kindly providing us with the Sp1 expression plasmid. We would also thank Dr. Adam Sowalsky (BIDMC, Harvard Medical School, Boston, USA) for reading through our manuscript.Author ContributionsConceived and designed the experiments: DJ SZ. Performed the experiments: DJ RL DM NL YW. Analyzed the data: DJ SC SZ. Contributed reagents/materials/analysis tools: SC. Wrote the paper: DJ SC SZ.Supporting InformationFigure S1 Detection of basal activity of the MGARP promoter by red fluorescence. (DOCX)
Homooligomeric proteins have large interface areas between the subunits resulting in stable complexes [1?]. Because the molecular functions of homooligomers often require their complete oligomeric forms, the overall structure of a homooligomer may help understand its molecular function [5,6]. It is known that the complex structure of a homooligomer often assumes a symmetric structure [7], with the subunits arranged in either a `close-packed’ (or dihedral) form or a `ring’ form [8]. The close-packed form has n/2-fold rotational symmetry around one rotational axis (designated as Dn where n is the number of subunits; axis 1 in Figure 1B) and 2-fold rotational symmetry around the other rotational axes (axes 2? in Figure 1B) perpendicular to the first rotational axis. Oligomers with this form contain an even number of subunits. In a statistical analysis of the Protein Data Bank (PDB) [9] (see Materials and Methods), we found that homooligomers composed of even numbers of subunits are dominant (Figure 1C) because of the abundance of 23115181 the closepacked oligomers. In the close-packed form, the subunit interfaces are arranged in a face-t.
