It has become increasingly evident that transcription elongation by RNA polymerase II (pol II) is a critical step in eukaryotic gene expression. More than twenty elongation factors regulating this process have been identified so far by biochemical and genetic studies. Our lab is focusing on elucidating the roles of elongation factors, especially Elongin A- and Elongin BC-related proteins, in mammalian cell growth, differentiation, development and human diseases.
The synthesis of mRNA in eukaryotes is regulated by the concerted action of a set of transcription factors that control the activity of RNA polymerase II (pol II) during the initiation and elongation stages of transcription. Although the initiation stage of transcription by pol II was long thought to be the primary site for regulation, a growing body of evidence indicates that transcript elongation can also be rate-limiting and is an important target for gene regulation by a diverse collection of elongation factors that promote efficient elongation of transcripts by pol II in vitro. Elongin is a member of a family of elongation factors that can increase the overall rate of RNA chain elongation by decreasing the frequency and/or duration of transient pausing by pol II as it traverses the DNA template [Fig. 1] (Aso, Conaway & Conaway FASEB J. 1995; Aso et al. J. Clin. Invest. 1996; Kwak and Lis Annu. Rev. Genet. 2013).
Elongin is a 3-subunit complex composed of the transcriptionally active Elongin A subunit and two positive regulatory subunits Elongins B and C, which share sequence similarity with ubiquitin and with the Skp1 subunit of SCF ubiquitin ligases, respectively (Aso et al. Science 1995). Elongin A binds Elongins B and C through a sequence motif referred to as the BC-box (Aso et al. EMBO J. 1996). Elongins B and C are subunits not only of the Elongin complex, but also of members of a large
family of Cullin 2 (Cul2)- or Cullin 5(Cul5)-based ubiquitin ligases, in which a BC-box containing substrate recognition subunit is linked through the Elongin BC heterodimer to a subcomplex composed of Cul2 or Cul5 and either of the small RING finger proteins Rbx1 or Rbx2. We and others have shown recently that Elongin A can act as the BC-box substrate recognition subunit of a Cul5- and Rbx2-containing ubiquitin ligase that ubiquitylates the largest subunit of pol II (Rpb1) [Fig. 2] (Yasukawa et al. EMBO J. 2008).
Although mammalian Elongin A is not essential for cell viability in vitro, Elongin A is essential in vivo. Elongin A-deficient (Elongin A-/-) mouse embryos exhibit developmental abnormalities including central nervous system (CNS) anomalies and die between days 10.5 and 12.5 of gestation (Yamazaki et al. J. Biol Chem. 2003; Miyata and Yasukawa et al. Cell Death Differ. 2007). In addition, Elongin A has been shown to be required for optimal expression of the stress response genes ATF3 and p21 in response to several stimuli (Kawauchi et al. J. Biol Chem. 2013). Because Rpb1 ubiquitylation following pausing or arrest of pol II is now believed to be one mechanism that helps to ensure the overall efficiency of transcript elongation,
it remains unclear which activity of Elongin A, transcriptional elongation or Rpb1 ubiquitylation, in fact plays a more crucial role in gene expression in vivo. Recently, we have demonstrated that Elongin A-/- mouse embryos and Elongin A-/- embryonic stem (ES) cells exhibit impaired neuronal development and differentiation, respectively [Figs. 3, 4]. Furthermore, we have shown that Elongin A mutants that are defective in Rpb1 ubiquitylation but retain the ability to stimulate transcript elongation can rescue neuronal differentiation and retinoic acid (RA)-induced up-regulation of a subset of neurogenesis-related and other genes in Elongin A-/- ES cells. Taken together, our results suggest that the elongation stimulatory activity of mammalian Elongin A plays a crucial role in the timely expression of a subset of genes required for neuronal development [Fig. 5] (Yasukawa et al. Cell Rep. 2012).
Weems J.C., Slaughter B.D., Unruh J.R., Boeing S., Hall S.M., McLaird M.B., Yasukawa T., Aso T., Svejstrup J.Q., Conaway J.W., and Conaway,R.C.
Cockayne syndrome B protein regulates recruitment of the Elongin A ubiquitin ligase to sites of DNA damage.
J. Biol. Chem. 292, 6431-6437, 2017.
Weems J.C., Slaughter B.D., Unruh J.R., Hall S.M., McLaird M.B., Gilmore J.M., Washburn M.P., Florens L., Yasukawa, T., Aso, T., Conaway, J.W., and Conaway, R.C.
Assembly of the Elongin A ubiquitin ligase is regulated by genotoxic and other stresses.
J. Biol. Chem. 290, 15030-15041, 2015.
Kawauchi, J., Inoue, M., Fukuda, M., Uchida, Y., Yasukawa, T., Conaway, R.C., Conaway, J.W., Aso, T., and Kitajima, S. Transcriptional properties of mammalian Elongin A and its role in stress response.
J. Biol. Chem. 288, 24302-24315, 2013.
Yasukawa, T., Bhatt, S., Takeuchi, T., Kawauchi, J., Takahashi, H., Tsutsui, A., Muraoka, T., Inoue, M., Tsuda, M., Kitajima, S., Conaway, R.C., Conaway, J.W., Trainor, P.A., and Aso, T. Transcriptional elongation factor Elongin A regulates retinoic acid-induced gene expression during neuronal differentiation.
Cell Rep. 2, 1129-1136, 2012.
Yamada, K., Tamamori-Adachi, M., Goto, I., Iizuka, M., Yasukawa, T., Aso, T., Okazaki, T., and Kitajima, S. Degradation of p21Cip1 through APC/CCdc20 mediated ubiquitylation is inhibited by cyclin dependent kinase 2 in cardiomyocytes.
J. Biol. Chem. 286, 44057-44066, 2011.
Yasukawa, T., Kamura, T., Kitajima, S., Conaway, R.C., Conaway, J.W., and Aso, T.
Mammalian Elongin A complex mediates DNA-damage-induced ubiquitylation and degradation of Rpb1.
EMBO J. 27, 3256-3266, 2008. (Faculty of 1000 Biology)
Miyata, K.¶, Yasukawa, T.¶, Fukuda, M., Takeuchi, T., Yamazaki, K., Sakumi, K., Tamamori-Adachi, M., Ohnishi, Y., Ohtsuki, Y., Nakabeppu, Y., Kitajima, S., Onishi, S., and Aso, T.
Induction of apoptosis and cellular senescence in mice lacking transcription elongation factor, Elongin A.
Cell Death Differ. 14, 716-726, 2007. (¶ equal contribution)
Yasukawa, T., Sugimura, K., Fukuda, M., Yamazaki, K., Kitajima, S., Okumura, K., and Aso, T.
Functional characterization of a mammalian transcription factor, Elongin A.
Biochem. Biophys. Res. Commun. 352, 237-243, 2007.
Sugita, H., Fujimoto, M., Yasukawa, T., Shimizu, N., Sugita, M., Yasuhara, S., Martytn, J.A. and Kaneki, M.
Inducible nitric-oxide synthase and NO donor induce insulin receptor substrate-1 degradation in skeletal muscle cells.
J. Biol. Chem. 280, 14203-14211, 2005.
Yasukawa, T., Tokunaga, E., Ota, H., Sugita, H., Martyn, J.A. and Kaneki, M.
S-Nitrosylation-dependent inactivation of Akt/PKB in insulin resistance.
J. Biol. Chem. 280, 7511-7518, 2005.
Yamazaki, K., Aso, T., Ohnishi, Y., Ohno, M., Tamura, K., Shuin, T., Kitajima, S., and Nakabeppu, Y. Mammalian Elongin A is not essential for cell viability but is required for proper cell-cycle progression with limited alteration of gene expression.
J. Biol. Chem. 278, 13585-13589, 2003.
Yamazaki, K., Guo, L., Sugahara, K., Zhang, C., Enzan, H., Nakabeppu, Y., Kitajima, S., and Aso, T. Identification and biochemical characterization of a novel transcription elongation factor, Elongin A3.
J. Biol. Chem. 277, 26444-26451, 2002.
Zhang, C., Yong, C., Adachi, M.T., Oshiro, S., Aso, T., Kaufman, R.J., and Kitajima, S.
Homocysteine induces programmed cell death in human vascular endothelial cells through activation of the unfolded protein response.
J. Biol. Chem. 276, 35867-35874, 2001.
Matsuda, S., Yasukawa, T., Homma, Y., Shao, Z., Ito, Y., Niikura, T., Hiraki, T., Hirai, S., Ohno, S., Kita, Y., Kawasumi, M., Kouyama, K., Yamamoto, T., Kyriakis, J.M., Nishimoto, I. c-Jun N-terminal kinase (JNK)-interacting protein-1β/islet-brain-1 scaffolds Alzheimer's amyloid precursor protein with JNK.
J. Neurosci. 21, 6597-6607, 2001.
Hashimoto, Y., Niikura, T., Tajima, H., Yasukawa, T., Sudo, H., Ito, Y., Kita, Y., Kawasumi, M., Kouyama, K., Doyu, M., Sobue, G., Koide, T., Tsuji, S., Lang, J., Kurokawa, K., Nishimoto, I. A rescue factor abolishing neuronal cell death by a wide spectrum of familial Alzheimer's disease genes and Aβ.
Proc. Natl. Acad. Sci. U. S. A. 98, 6336-6341, 2001.
Sudo, H., Hashimoto, Y., Niikura, T., Shao, Z., Yasukawa, T., Ito, Y., Yamada, M., Hata, M., Hiraki, T., Kawasumi, M., Kouyama, K., and Nishimoto, I. Secreted Aβ does not mediate neurotoxicity by antibody-stimulated amyloid precursor protein.
Biochem. Biophys. Res. Commun. 282, 548-556, 2001.
Niikura, T., Hashimoto, Y., Okamoto, T., Abe, Y., Yasukawa, T., Kawasumi, M., Hiraki, T., Kita, Y., Terashita, K., Kouyama, K. and Nishimoto, I. GF-I protects cells from apoptosis by Alzheimer's V642I mutant APP through IGF-I receptor in an IGF binding protein-sensitive manner.
J. Neurosci. 21, 1902-1910, 2001.
Kokura, K., Kaul, S.C., Wadhwa, R., Nomura, T., Khan, M.M., Shinagawa, T., Yasukawa, T., Colmanares, C., Ishii, S. The Ski protein family is required for MeCP2-mediated transcriptional repression.
J. Biol. Chem. 276, 34115-34121, 2001.
Cai, Y., Zhang, C., Nawa, T., Aso, T., Tanaka, M., Oshiro, S., Ichijo, H., and Kitajima, S. Homocysteine-responsive ATF3 gene expression in human vascular endothelial cells: signal transduction pathway and promoter responsive element.
Blood 96, 2140-2148, 2000.
Aso, T., Yamazaki, K., Amimoto, K., Kuroiwa, A., Higashi, H., Matsuda, Y., Kitajima, S., and Hatakeyama, M. Identification and characterization of Elongin A2, a new member of an Elongin family of transcription elongation factors, specifically expressed in the testis.
J. Biol. Chem. 275, 6546-6552, 2000.
Aso, T., Yamazaki, K., Aigaki, T., and Kitajima, S.
Drosophila von Hippel-Lindau tumor suppressor complex possesses E3 ubiquitin ligase activity.
Biochem. Biophys. Res. Commun. 276, 355-361, 2000.
Sudo, H. ¶, Jiang, H. ¶, Yasukawa, T. ¶, Hashimoto, Y., Niikura, T., Kawasumi, M., Matsuda, S., Takeuchi, Y., Aiso, S., Matsuoka, M., Murayama, Y. and Nishimoto, I.
Antibody regulated neurotoxic function of cell surface β-amyloid precursor protein.
Mol. Cell. Neurosci. 16, 708-723, 2000. (¶ equal contribution)
Ohh, M., Takagi, Y., Aso, T., Stebbins, C.E., Pavletich, N.P., Zbar, B., Conaway, R.C., Conaway, J.W., and Kaelin, W.G. Synthetic peptides define critical contacts between elongin C, elongin B, and the von Hippel-Lindau tumor suppressor protein.
J. Clin. Invest. 104, 1583-1591, 1999.
Shinobu, N., Maeda, T., Aso, T., Ito, T., Kondo, T., Koike, K., and Hatakeyama, M. Physical interaction and functional antagonism between the RNA polymerase II elongation factor ELL and p53.
J. Biol. Chem. 274, 17003-17010, 1999.
Tokitou, F., Nomura, T., Khan, M.M., Kanl, S.C., Wadhwa, K., Yasukawa, T., Kohno, I. and Ishii, S. Viral ski inhibits retinoblastoma protein (Rb)-mediated transcriptional repression in a dominant negative fashion.
J. Biol. Chem. 274, 4485-4488, 1999.
Aso, T., and Conrad, M.N. Molecular cloning of DNAs encoding the regulatory subunits of Elongin from Saccharomyces cerevisiae and Drosophila melanogaster.
Biochem. Biophys. Res. Commun. 241, 334-340, 1997.
Pan, G., Aso, T., and Greenblatt, J.
Interaction of elongation factors TFIIS and elongin A with a human RNA polymerase II holoenzyme capable of promoter-specific initiation and responsive to transcriptional activators.
J. Biol. Chem. 272, 24563-24571, 1997.
Aso, T., Haque, D., Barstead, R.J., Conaway, R.C., and Conaway, J.W. The inducible elongin A elongation activation domain: structure, function and interaction with the elongin BC complex.
EMBO J. 15, 5557-5566, 1996.
Aso, T., Shilatifard, A., Conaway, J.W., and Conaway, R.C.
Transcription syndromes and the role of RNA polymerase II general transcription factors in human disease.
J. Clin. Invest. 97, 1561-1569, 1996.
Dai, P., Akimaru, H., Tanaka, T., Hou, D-X., Yasukawa, T., Kanei-Ishi, C., Takahashi, T. and Ishii, S.
CBP as a transcriptional coactivator of c-Myb.
Genes Dev. 1, 528-540, 1996.
Aso, T., Lane, W.S., Conaway, J.W., and Conaway, R.C.
Elongin (SIII) : A multisubunit regulator of elongation by RNA polymerase II.
Science 269, 1439-1443, 1995.
Duan, D.R., Pause, A., Burgess, W.H., Aso, T., Chen, D.Y.T., Garrett, K.P., Conaway, R.C., Conaway, J.W., Linehan, W.M., and Klausner, R.D.
Inhibition of transcription elongation by the von Hippel-Lindau tumor suppressor protein.
Science 269, 1402-1406, 1995.
Garrett, K.P. ¶, Aso, T. ¶, Bradsher, J.N., Foundling, S.I., Lane, W.S., Conaway, R.C., and Conaway, J.W. Positive regulation of general transcription factor SIII by a tailed ubiquitin homolog.
Proc. Natl. Acad. Sci. U. S. A. 92, 7172-7176, 1995. (¶ equal contribution)
Aso, T., Conaway, J.W., and Conaway, R.C. The RNA polymerase II elongation complex.
FASEB J. 9, 1419-1428, 1995.
Mizuguchi, G., Kanei-Ishii, C., Takahashi, T., Yasukawa, T., Nagase, T., Horikoshi, M., Yamamoto, T. and Ishii, S. c-Myb repression of c-erbB-2 transcription by direct binding to the c-erbB-2 promoter.
J. Biol. Chem. 270, 9384-9389, 1995.
Yasukawa, T., Kanei-Ishii, C., Maekawa, T., Fujimoto, J., Yamamoto, T. and Ishii, S.
Increase of solubility of foreign proteins in Eschericha coli by coproduction of the bacterial thioredoxin.
J. Biol. Chem. 270, 25328-25331, 1995.
Aso, T., Serizawa, H., Conaway, R.C., and Conaway, J.W. A TATA sequence-dependent transcriptional repressor activity associated with mammalian transcription factor IIA.
EMBO J. 13, 435-445, 1994.
Aso, T., Conaway, J.W., and Conaway, R.C.
Role of core promoter structure in assembly of the RNA polymerase II preinitiation complex.
J. Biol. Chem. 269, 26575-26583, 1994.
Tan, S, Aso, T., Conaway, R.C., and Conaway, J.W. Roles of both the RAP30 and RAP74 subunits of transcription factor IIF in transcription initiation and elongation by RNA polymerase II.
J. Biol. Chem. 269, 25684-25691, 1994.
Kanei-Ishii, C., Yasukawa, T., Morimoto, R.I. and Ishii, S. c-Myb-induced trans activation mediated by heat shock elements without sequence-specific DNA binding of c-Myb.
J. Biol. Chem. 269, 15768-15775, 1994.
Yonaha, M., Aso, T., Kobayashi, Y., Vasavada, H., Yasukochi, Y., Weissman, S.M., and Kitajima, S. Domain structure of a human general transcription initiation factor, TFIIF.
Nucleic Acid Res. 21, 273-279, 1993.
Sarai, A., Uedaira, H., Morii, H., Yasukawa, T., Ogata, K., Nishimura, Y. and Ishii, S.
Thermal stability of the DNA-binding domain of the Myb oncoprotein.
Biochemistry 39, 7759-7764, 1993.
Tanikawa, J., Yasukawa, T., Enari, M., Ogata, K., Nishimura, Y., Ishii, S. and Sarai, A.
Recognition of specific DNA sequences by the c-myb protooncogene product: Role of three repeat units in the DNA-binding domain.
Proc. Natl. Acad. Sci. U. S. A. 90, 9320-9324, 1993.
Aso, T., Vasavada, H., Kawaguchi, T., Germino, F.J., Ganguly, S., Kitajima, S., Weissman, S.M., and Yasukochi, Y. Characterization of cDNA for the large subunit of the transcription initiation factor TFIIF.
Nature 355, 461-464, 1992.
|Professor: Teijiro Aso
|Assistant Lecturer: Takashi Yasukawa
Kochi Medical School
Department of Functional Genomics