Dr. Laura Bridgewater, Department of Microbiology & Molecular Biology

The goal of this project was to elucidate the role that nBMP-2 plays in Ca2+ transport. In the previous year, we demonstrated that mice that have no nBMP-2 in the nuclei of their cells exhibit delays in the transport of Ca2+ back into the sarcoplasmic reticulum after each muscle contraction. During the period of this award we have extended our focus on nBMP-2 and Ca2+ transport to its effects on neurological function, since learning and memory are also dependent on intracellular Ca2+ transport. To do so, we collaborated with Dr. Jeff Edwards, a neuroscientist in the Department of Physiology and Developmental Biology. This work has led to some very exciting results, as outlined below.

Achievement of academic objectives

The primary academic objective of this project was to determine whether the Ca2+-related phenotype of nBMP-2 elimination in mouse affects neurological function. Working with Dr. Edwards, we found that the nMP-2 mutant mice have significantly reduced synaptic plasticity, the main cellular mechanism mediating learning and memory. This work is now in preparation to be submitted within the month.

Evaluation of the mentoring environment

My lab operated well over the past year as a successful mentoring environment. We’ve had one Ph.D. student and two M.S. students, senior undergraduates who have been in my lab for as much as two years, and new undergraduates who have worked closely with the senior undergraduates to learn techniques, lab safety, and experimental design and interpretation. We hold lab meeting on Friday every week, and each student shows his or her results from the past week’s experiments. If a student has had technical problems, we all help in trouble-shooting. Besides providing each student with regular feedback on their work, this meeting also has been invaluable in broadening each student’s understanding of science in general and of the other projects going on in the lab. It has been gratifying to see the students grow and develop, increasing in independence as they become more comfortable performing techniques and can begin looking at the bigger picture of the work we’re doing. I’ve also spent a significant amount of time in one-on-one conversations with my students, about their research and also about such things as making decisions and setting priorities in life. I believe these interactions have been beneficial for the students.

Students involved and academic deliverables produce

Students involved

Publications in preparation, which have been supported in part by this MEG grant

1. Cordner, R.D., Ventura, J.S., Mayo, J.L., Andreasen, B., Barrow, J.R., Edwards, J.G., Capecchi, M.R., and Bridgewater, L.C. Mice bearing a targeted mutation of nBmp2 display decreased memory capability. In preparation
2. Bridgewater, L.C., Mayo, J.L., Evanson, B.G., Schmidt, A.D., Fox, C.L., Wallace, N.B., Loganathan, S.K., Adam, M.M., Nichols, C.A., Barrow, J.R., Parcell, A.C., Capecchi, M.R., and Hancock, C.R. Nuclear bone morphogenetic protein 2 (nBmp2) mutant mice exhibit impaired skeletal muscle relaxation. In revision.
3. Loos, T.J., Cordner, R.D., and Bridgewater, L.C. Nuclear Bmp4: A novel SCF E3 ubiquitin ligase interacting protein. In preparation.

Grant proposal

The results obtained in research supported by this MEG funding provided Preliminary studies for an NIH grant proposal submitted October 25, 2011, entitled “Nuclear variants of bone morphogenetic proteins.” If funded on the first submission, this grant would provide $450,000 in total costs over a three year period, beginning in July of 2012.

Description of Results/Findings

Last year’s MEG-funded work revealed that mutation of nBMP-2 in mice causes Ca2+ handling problems in skeletal muscle. This year we have demonstrated, with the help of neuroscience expert Dr. Jeff Edwards of the PDBIO Department, that our nBMP-2 mutant mice also have learning and memory problems that are likely linked to Ca2+ handling problems in the brain. This was demonstrated using long term potentiation (LTP) studies in hippocampal slices from control and mutant mice. We are currently preparing this work for publication and expect to submit it within the month.

We also conducted transient transfection tissue culture studies in an effort to identify ways that nBMP- 2 might exert its molecular impact on Ca2+ transport. We discovered that nBMP-2, while having no independent transcriptional activity, cooperates with the master chondrogenic transcription factor SOX9 to increase its activity by as much at 200%. This discovery is the key piece of data that supports our most recent NIH grant proposal mentioned above.

Summary of spending

The following student was paid wages from this MEG project funding in 2011:

• Aubrey Rogers, $8.50/hr, up to 20 hrs week Jan-Oct ($6,800)
• The majority of students working on the project this year worked for research credits

The rest of the budget was spent on the following:

• Animal care costs, WIDB specific pathogen free (SPF) facility ($3,700)
• PCR enzymes and primers for genotyping the mice ($2,000)
• Enzymes for building DNA constructs ($1,500)
• Tissue culture media, serum, flasks, and transfection reagents ($4,000)
• Dual luciferase assay kits for reading transfection results ($2,000)