Associate Professor of Molecular Biology & Genetics
439 Biotechnology Building
Jun "Kelly" Liu is an Associate Professor of Molecular Biology and Genetics. She received a B.S. degree in Biology at Wuhan University in China and a Ph.D. in Biochemistry, Molecular and Cell Biology from Cornell University. She did her postdoctoral research at the Carnegie Institution of Washington, Department of Embryology, where she was awarded a National Institutes of Health Postdoctoral Fellowship. She joined the faculty at Cornell in 2001. She is in the graduate fields of Genetics & Development, and Biochemistry, Molecular & Cell Biology.
BioMG 3850: http://courses.cit.cornell.edu/biomg3850
Mesoderm patterning and fate diversification
The mesoderm germ layer gives rise to a diverse array of functionally important cell types, including various types of muscle and non-muscle cells. We are interested in understanding the regulatory networks underlying the diversification of the mesoderm. We use the C. elegans postembryonic mesoderm lineage, the M lineage, as a model system for these studies. The M lineage is derived from a single pluripotent precursor cell, the M mesoblast, which during postembryonic development, divides in a characteristic and reproducible pattern to generate striated muscles, non-striated muscles as well as non-muscle mesodermal cells.The M lineage is therefore ideally suited to studies of how different mesodermal fates are diversified from a single pluripotent progenitor cell at single cell resolution.Most of the factors that we have identified are conserved in vertebrates, suggesting similar mechanisms shared by C. elegans and vertebrates in mesoderm diversification.
Modulation of BMP signaling
Bone morphogenetic proteins (BMPs) belong to the transforming growth factor beta (TGFbeta) superfamily of ligands. The BMP signaling pathway plays roles in multiple developmental and homeostatic processes. We are interested in uncovering mechanisms involved in ensuring proper spatiotemporal control of BMP signaling.During the course of our studies of mesoderm development in C. elegans, we have devised an easy and sensitive genetic approach to identify new components of the BMP-like pathway in C. elegans. We are currently using a combination of genetic, genomic, molecular and biochemical approaches to identify and determine how each gene product functions in modulating BMP signaling.
Functions of the nuclear lamina
A major component of the nuclear envelope is the nuclear lamina, a meshwork of intermediate filament lamin proteins, located next to the nucleoplasmic side of the inner nuclear membrane. In addition to providing structural support for the nucleus, lamins help regulate many different nuclear processes, such as DNA replication, transcription and chromatin organization. Mutations in genes encoding nuclear lamina proteins cause a diverse array of human diseases (laminopathies) with remarkable tissue specificity, such as muscular dystrophies, lipodystrophies, neuropathies and progeria syndromes. We are currently using C. elegans as a model system to determine how the nuclear lamina carries out cell-type- and developmental-stage-specific functions. Results from these studies may help us better understand the molecular mechanisms underlying nuclear envelope-associated human diseases.
For more information on our research, please visit the Liu Lab website.
Click here to view Dr. Liu's PubMed listings.
Barkan, R., Zahand, A. J., Sharabi, K., Lamm, A. T., Feinstein, N., Haithcock, E., Wilson, K. L., Liu, J. and Gruenbaum, Y. (2012) Emerin the LEM2: essential roles in C. elegans development, muscle function and mitosis. Mol Biol Cell. 2011 Dec 14. [Epub ahead of print] (Pubmed)
Krause, M. and Liu, J. (2011) Somatic muscle specification during embryonic and post-embryonic development in the nematode C. elegans. WIREs Developmental Biology. DOI: 10.1002/wdev.15. Published Online: Dec 08 2011. (Pubmed)
Tian, C., Shi, H., Colledge, C., Stern, M., Waterston, R. and Liu, J. (2011) The C. elegans SoxC protein SEM-2 opposes differentiation factors to promote a proliferative blast cell fate in the postembryonic mesoderm. Development. 138: 1033-1043. Epub 2011 February 9. (Pubmed)
Tian, C., Sen, D., Shi, H., Foehr, M. L., Plavskin, Y. Vatamaniuk, O. K. and Liu, J. (2010) The RGM protein DRAG-1 positively regulates a BMP-like signaling pathway in Caenorhabditis elegans. Development. 137: 2375-2384. Epub 2010 June 9. (Pubmed)
Amin, N.M., Shi, H. and Liu, J. (2010) The FoxF/FoxC factor LET-381 directly regulates both cell fate specification and cell differentiation in C. elegans mesoderm development. Development. 137:1451-1460. Epub 2010 Mar 24.
Jiang, Y., Shi, H. and Liu, J. (2009) Two Hox cofactors, the Meis/Hth homolog UNC-62 and the Pbx/Exd homolog CEH-20, function together during C. elegans postembryonic mesodermal development. Developmental Biology. 334:535-546. (Pubmed)
Amin, N. M., Lim, S.-E., Shi, H., Chan, T. L. and Liu, J. (2009) A conserved Six-Eya cassette acts downstream of Wnt signaling to direct non-myogenic versus myogenic fates in the C. elegans postembryonic mesoderm. Developmental Biology. 331:350-360. (Pubmed)
Golden, A., Liu, J. and Cohen-Fix, O. (2009) Inactivation of the C. elegans homolog of lipin leads to endoplasmic reticulum disorganization and defects in nuclear envelope breakdown and reassembly of the nuclear envelope.. J. Cell Sci. 122: 1970-1978. (Pubmed)
Lei, H., Liu, J., Fukushige, T., Fire, A., and Krause, M. (2009) Caudal-like PAL-1 directly activates the bodywall muscle module regulator HLH-1 in C. elegans to initiate embryonic muscle gene regulatory network. Development 136: 1241-1249. Epub 2009 Mar 4. (Pubmed)
Liu, J. (March 2009) Nuclear Envelope and Lamins: Organization and Dynamics. In: ENCYCLOPEDIA OF LIFE SCIENCES. John Wiley & Sons, Ltd: Chichester http://www.els.net/ [DOI: 10.1002/9780470015902.a0001342.pub2].
Jiang, Y., Shi, H., Amin, N. M., Sultan, I. and Liu, J. (2008) Mesodermal expression of the C. elegans HMX homolog mls-2 requires the PBC homolog CEH-20. Mech. Dev. 125: 451-461. Epub 2008 Feb 2. (Pubmed)
Foehr, M. L. and Liu, J. (2008) Dorsoventral patterning of the C. elegans postembryonic mesoderm requires both LIN-12/Notch and TGF-beta signaling. Dev. Biol. 313: 256-266. Epub 2007 Oct 25. (Pubmed)
Amin, N. M., Hu, K., Pruyne, D., Terzic, D., Bretscher, A. and Liu, J. (2007) A Zn finger/FH2 domain containing protein FOZI-1 acts redundantly with CeMyoD to specify striated body wall muscle fates in the C. elegans postembryonic mesoderm. Development 134: 19-29. Epub 2006 Nov 30. (Pubmed)
Johnston R. J. Jr., Copeland, J. W., Fasnacht, M., Etchberger, J. F., Liu, J., Honig, B. and Hobert, O. (2006) An unusual Zn-finger/FH2 domain protein controls a left/right asymmetric neuronal fate decision in C. elegans. Development 133: 3317-3328. (Pubmed)
Foehr, M. F., Lindy, A. S., Fairbank, R. C., Amin, N. M., Xu, M., Yanowitz, J., Fire, A. Z. and Liu, J. (2006) An antagonistic role for the C. elegans Schnurri homolog SMA-9 in modulating TGF-� signaling during mesodermal patterning. Development 133: 2887-2896. (Pubmed)
Haithcock, E., Dayani, Y., Neufeld, E., Zahand, A. J., Feinstein, N., Mattout, A., Gruenbaum, Y. and Liu, J. (2005) Age-related changes of nuclear architecture in C. elegans. Proc Natl Acad Sci U S A. 102: 16690-16695. (PubMed)
This article was highlighted in the same issue of PNAS 102: 16531, and featured in a commentary by Wilson, K.L. (2005) PNAS 102: 18767-18768 (Pubmed) and a News and Views article by Lans and Hoejimakers (2006) Nature 440: 32-34 (Pubmed).
Jiang, Y., Horner, V. and Liu, J. (2005) The HMX homeodomain protein MLS-2 regulates cleavage orientation, cell proliferation and cell fate specification in the C. elegans postembryonic mesoderm. Development 132: 4119-4130.(PubMed)
Margalit, A., Liu, J., Fridkin, A., Wilson, K. L. and Gruenbaum, Y. (2005) A lamin-dependent pathway that regulates nuclear organization, cell cycle progression and germ cell development. Novartis Found Symp. 264: 231-240; discussion 240-245.(PubMed)
Liang, J., Lints, R., Foehr, M. L., Tokarz, R., Yu, L., Emmons, S. W., Liu, J. and Savage-Dunn, C. (2003) The Caenorhabditis elegans schnurri homolog, sma-9, mediates stage- and cell type- specific responses to dbl-1 BMP-related signaling. Development 130: 6453-6464. (PubMed)
Liu, J., Lee, K. K., Segura-Totten, M., Neufeld E., Wilson, K. L. and Gruenbaum, Y. (2003) MAN1 and emerin have overlapping function(s) essential for chromosome segregation and cell division in Caenorhabditis elegans. Proc Natl Acad Sci U S A. 100:4598-4603. (PubMed)
Lee, K. K., Starr, D., Cohen, M., Liu, J., Han, M., Wilson, K. L. and Gruenbaum Y. (2002) Lamin-dependent localization of UNC-84, a protein required for nuclear migration in Caenorhabditis elegans. Mol. Biol. Cell 13: 892-901. (PubMed)
Gruenbaum, Y., Lee, K. K., Liu, J., Cohen, M. and Wilson, K. L. (2002) The expression, lamin-dependent localization and RNAi depletion phenotype for emerin in C. elegans. J. Cell Sci. 115: 923-929. (PubMed)
Lee, K. K., Gruenbaum, Y., Spann, P., Liu, J. and Wilson, K. L. (2000) C. elegans nuclear envelope proteins Emerin, MAN1, lamin, and nucleoporins reveal unique timing of nuclear envelope breakdown during mitosis. Mol. Biol. Cell 11: 3089-3099. (PubMed)
Liu, J., Ben-Shahar, T. R., Riemer, D., Treinin, M., Spann, P., Weber, K., Fire, A. and Gruenbaum, Y. (2000). Essential roles for Caenorhabditis elegans lamin gene in nuclear organization, cell cycle progression and spatial organization of nuclear pore complexes. Mol. Biol. Cell 11: 3937-3947. (PubMed)
Liu, J., and Fire, A. (2000). Overlapping roles of two Hox genes and the exd ortholog ceh-20 in diversification of the C. elegans postembryonic mesoderm. Development 127: 5179-5190. (PubMed)
Harfe, B. D., Gomes, A. Z., Kenyon, C., Liu, J., Krause, M. and Fire, A. (1998) Analysis of a Caenorhabditis elegans twist homolog identifies conserved and divergent aspects of mesodermal patterning. Genes & Dev. 12: 263-2635. (PubMed)
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