Research interests:
regeneration, skeletal morphogenesis, cell-cell communication, extracellular matrix, hyaluronic acid, semaphorins, developmental biology, genetics
My lab is interested how the bones of the skeleton achieve the correct size. To examine this problem we study regeneration of the zebrafish fin skeleton. Fins grow by the addition of new bony fin ray segments to the distal ends of the fin rays, and fin length is regulated by mechanisms controlling both the number and length of those segments. Therefore, the segment represents the unit of bone growth in the fin.
Identification of the mutations causing phenotypes affecting segment length will reveal genetic and molecular pathways underlying segment growth. For example, we showed that mutations in the gap junction gene connexin43 cause the short fin phenotypes of reduced fin length, reduced segment length, and reduced cell proliferation. Our research suggests that Cx43 activity coordinates skeletal growth (i.e. cell proliferation) and patterning (i.e. joint formation).
The goal of my lab is to reveal how defects in Cx43-based gap junctional intercellular communication mediate skeletal morphogenesis. Using a microarray, we identified and validated several genes whose expression appears to depend on the level of Cx43 activity. We are finding that Cx43 function seems to regulate the expression of genes that function in, or modify, the extracellular environment. Thus, we identified the secreted growth factor, Sema3d, as mediating independent intercellular signaling pathways that control cell proliferation and joint formation (Ton and Iovine, 2012). We also find that the hyaluronan-based extracellular matrix contributes to these pathways (Govindan and Iovine, 2014). Most recently, we showed that the collagen-based actinotrichia are necessary for normal levels of cell proliferation and for normal placement of joints (Bhadra and Iovine, 2015). Because of the location of actinotrichia between the compartment of dividing cells and the compartment of cells that differentiate into bone and joint forming cells, we suggest that the integrity of actinotrichia signals to both compartments to coordinate growth and patterning. We are in the process of validating additional genes, and we continue to build a Cx43-dependent network in order to provide new insights into the pathways that can be regulated by gap junctional communication.
Bhattacharya, S., Gargiulo, D., Iovine, M.K. Simplet-dependent regulation of beta-catenin signaling influences skeletal patterning downstream of Cx43. Development. doi:10.1231/dev.166975.
Dardis, G., Tryon, R., Ton, Q., Johnson, S.L., Iovine, M.K. Cx43 suppresses evx1 expression to regulate joint initiation in the regenerating fin. Developmental Dynamics. doi: 10.1002/dvdy.24531. 2017.
Banerji, R., Eble, D.M., Iovine, M.K., Skibbens, R.V. Esco2 Regulates cx43 Expression During Skeletal Regeneration in the Zebrafish Fin. 2016. Developmental Dynamics 245:7-21. doi: 10.1002/DVDY.24354
Barton, R., Khakbaz, P., Bera, I. Klauda, J.B., Iovine, M.K., Berger, B.W. 2016 Interplay of Specific Trans- and Juxtamembrane Interfaces in Plexin A3 Dimerization and Signal Transduction. Biochemistry 55: 4928-4938. doi: 10.1021/acs.biochem.6b00517
Misu, A., Yamanaka, H. Aramaki, T., Kondo, S., Skerrett, I.M., Iovine, M.K., Watanabe, M. 2016. Two Different Functions of Connexin43 Confer Two Different Bone Phenotypes in Zebrafish. J. of Biological Chemistry. 291: 24, 12601-12611. doi: 10.1074/jbc.M116.720110
Govindan, J., Tun, KM., Iovine, M.K. Cx43-Dependent Skeletal Phenotypes Are Mediated by Interactions between the Hapln1a-ECM and Sema3d during Fin Regeneration. 2016. PLoS ONE 11(2):
e0148202. doi:10.1371/journal.pone.0148202Bhadra, J, Banerji, R., Singh, J., Sallada, N., Eble, D.M., and Iovine, M.K. The zebrafish fibroblast cell line AB9 as a tool to complement gene regulation studies. Musculoskeletal Research. doi:10.14800/mr.992. 2015.
Bhadra, J. and Iovine, M.K. Hsp47 mediates Cx43-dependent skeletal growth and patterning in the regenerating fin. Mechanisms of Development. doi: 10.1016/j.mod.2015.06.004. 2015.
Govindan, J. and Iovine, M.K. Dynamic remodeling of the extra cellular matrix during zebrafish fin regeneration. Gene expression patterns. doi: 10.1016/j.gep.2015.06.001. 2015.
Barton, R., Driscoll, A., Flores, S., Mudbhari, D., Collins, T., Iovine, MK, Berger, B.W., Cysteines in the neuropilin-2 MAM domain modulate receptor homooligomerization and signal transduction. Biopolymers. doi: 10.1002/bip.22619. 2015.
Barton, R., Palacio, D., Iovine, M. K., Berger, B.W., A Cytosolic Juxtamembrane Interface Regulates Plexin A3 Oligomerization and Signal Transduction. PLoS One. doi: 10.1371/journal.pone.0116368. 2015.
Govindan, J. and Iovine, M.K. Hapln1a is required for Connexin43-dependent growth and patterning in the regenerating fin skeleton. PLoS One. doi:10.1371/journal.pone.0088574. 2014.
Ton, Q.T. and Iovine, M.K. Identification of an evx1-dependent joint-formation pathway during fin regeneration. PLoS One. doi: 10.1371/journal.pone.0081240. 2013.
Ton, Q.T. and Iovine, M.K. Semaphorin3d mediates Cx43-dependent phenotypes during fin regeneration. Dev. Biol. 366: 195-203. 2012.
Gerhardt, S.V., Jefferis, R., and Iovine, M.K., Cx40.8, a Cx43-like protein, forms gap junction channels inefficiently and may require Cx43 for its association at the plasma membrane. FEBS Letters. 583: 3419-3424. 2009.
Brown, A.M., Fisher, S., and Iovine, M.K., Osteoblast maturation occurs in overlapping proximal-distal compartments during fin regeneration in zebrafish. Dev. Dyn. 238: 2922-2928. 2009.Sims, K, Eble, D.M., and Iovine, M.K., Connexin43 regulates joint location in zebrafish fins. /Dev Biol./ *327:* 410-418. 2009.
Hoptak-Solga, A.D., Nielsen, S., Jain, I., Thummel, R., Hyde D., and Iovine, M.K. Connexin43 is required in the population of dividing cells during fin regeneration. /Dev. Biol./ *317:* 541-548. 2008.
Iovine, M.K., Gumpert, A. Falk, M., Mendelson, T.C. Cx23, a connexin with only four extracellular-loop cysteines, forms functional gap junction channels and hemichannels. FEBS Letters. 582: 165-170. 2008.
Hoptak-Solga, A.D., Klein, K.A., DeRosa, A.M. White, T.W., and Iovine, M.K. Zebrafish short fin mutations in connexin43 lead to aberrant gap junctional intercellular communication. FEBS Letters. 581: 3297-3302. 2007.
Jain, I., Stroka, C., Yan, J., Huang, W.M., and Iovine, M.K. Bone growth in zebrafish fins occurs via multiple pulses of cell proliferation. Dev. Dyn. 236: 2668-2674. 2007.Goldsmith, M.I., Iovine, M.K., O'Reilly-Pol, T., Johnson, S.L. A developmental transition in growth control during zebrafish caudal fin development. Dev. Biol. 296: 450-457.2006.
Eastman, S.D., Chen, T.H., Falk, M.M., Mendelson, T.C., and Iovine, M.K. Phylogenetic analysis of three complete gap junction gene families reveals lineage-specific duplications and highly supported gene classes. Genomics. 87: 265-274. 2006.
Iovine, M.K., Higgins, E.P., Hindes, A., Coblitz, B., and Johnson, S.L. Mutations in connexin43 (GJA1) perturb bone growth in zebrafish fins. Dev. Biol. 278: 208-219. 2005.
Iovine and Johnson, 2002. A Genetic, Deletion, Physical, and Human Homology Map of the long fin Region on Zebrafish Linkage Group 2. Genomics. 79: 756-759.
Iovine and Johnson, 2000. Genetic Anaylsis of Isometric Growth Control Mechanisms in the Zebrafish Caudal Fin. Genetics. 155: 1321-1329.
Reviews
Banerji, R., Skibbens, R.V., Iovine, M.K. How many roads lead to cohesinopathies? Developmental Dynamics. doi: 10.1002/dvdy.24510. 2017. Invited review.
Holtzman, N.G., Iovine, M.K., Liang, J.O., Morris, J. Learning to Fish with Genetics: A Primer on the Vertebrate Model Danio rerio. 2016. Genetics. doi:10.1534/genetics.116.190843/-/DC1.
Ton, Q.T. and Iovine, M.K. Determining how defects in Connexin43 cause skeletal disease. genesis. doi:10.1002/dvg.22349. 2012. Invited review.
Iovine, M.K. Conserved mechanisms regulate outgrowth in zebrafish fins. Nature Chem. Biol. 3: 613-618. (2007).
Collaborative Publications
Gumm, J.M, Snekser, J, J.L., and Iovine, M.K., Association preferences of fin-mutant female zebrafish, Danio rerio. /Behavioral Processes/. *80:* 35-38. 2009.
Itkowitz M. and Iovine, M.K. Single gene mutations causing exaggerated fins also cause non-genetic changes in the display behavior of male zebrafish. Behavior. 144: 787-795. 2007
Mendelson, T.C., Imhoff, V.E., and Iovine, M.K. Analysis of early embryogenesis in Rainbow and Banded Darters (Percidae: Etheostoma) reveals asymmetric postmating barrier. Environ. Biol. Fish. 76: 351-360. 2006.
Current Lab Members
Rebecca Bowman
Lab Technician
Rajeswari Banerji
Graduate Student
Past Lab Members
2015 - from left to right: Harneel Riar, Rebecca Bowman, Joyita Bhadra, Jayalakshmi Govindan, M. Kathryn Iovine, Ph.D., Rajeswari Banerji
- Joyita Bhadra, Ph.D. - post-doctoral fellow at the Indian Institute of Science, Bangalore
- Jayalakshmi Govindan, Ph.D. - research associate at Princeton University
- Angela Hoptak, Ph.D. - instructor at Kutztown University
- Quynh Ton, Ph.D. - post-doctoral fellow at the University of Children's Hospital, Cincinnati