Difference between revisions of "Part:BBa K4165009"
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===WetLab Results===
 
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Tau was expressed in BL21 (DE3) to be purified using affinity chromatography to form aggregates that mimc tau in Alzheimer’s patient’s brain, those aggregates were used later to test the whole system. Tau was purified using affinity chromatography and characterized using BCA  
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Tau was expressed in BL21 (DE3) to be purified using affinity chromatography to form aggregates that mimc tau in Alzheimer’s patient’s brain, those aggregates were used later to test the whole system. Tau was purified using affinity chromatography and characterized using BCA and SDS
 
<p style=" font-weight: bold; font-size:14px;"> Transformation of His Tau in DH-5 alpha using pJET cloning vector </p>
 
<p style=" font-weight: bold; font-size:14px;"> Transformation of His Tau in DH-5 alpha using pJET cloning vector </p>
 
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Revision as of 15:20, 12 October 2022


Tau (0N4R)

This basic part encodes the human microtubule-associated tau protein isoform 0N4R.


Usage and Biology

Alzheimer's disease (AD), which is considered the most common neurodegenerative disease to cause dementia, is characterized by 2 main accumulations that are amyloid plaques from amyloid beta and NFTs aggregates resulting from hyperphosphorylated or abnormally phosphorylated tau protein accumulation. Our part Tau, microtubule-associated protein (MAP) is a phosphoprotein that is prevalently found in cytosol and neuron axons. It is determined to be significantly expressed in neurons of the central nervous system (CNS) and the ocular tissues. It has a crucial role both under normal physiological conditions and also in the pathology of Alzheimer's disease.

In the normal brain, it can stabilize the neuronal microtubules that are essential for the establishment of cell polarity, the development of cell processes, and intracellular signal transduction. Six molecular tau isoforms are coded by a single gene on chromosome 17 resulting from alternative splicing of tau pre-mRNA and characterized to be significantly hydrophilic, heat stable, and soluble. These six isoforms differ in their binding repeats either 3R taus or 4R taus microtubule-binding repeats and the extra 4R repeat comes from the second (R2) repeat found in 4R. Tau biological activity is affected by 2 main processes that are alternative splicing and phosphorylation. For tau's interaction with tubulin and the enhancement of microtubule assembly, normal brain tau appears to require 2-3 moles of phosphate per mole of the protein. However, tau is phosphorylated at Ser262 and Ser214 in AD, which causes tau to separate from microtubules.

In the AD brain, tau Hyperphosphorylation is considered the main cause of AD progression, it may alter the protein's shape and charge, which in turn causes the microtubule-binding domain to become exposed and allow tau to self-assemble and form oligomers characterized to be neurofibrillary tangle. According to several studies, the polymerized tau (neurofibrillary tangles) is inert since it does not bind to tubulin or encourage its assembly into microtubules.

Before the development of NFTs, all six forms of tau are self-assembled into paired helical filaments as a result of hyperphosphorylation at the C-terminus of tau (PHFs). The aggregated tau protein takes this shape, which impairs axonal transit and continuously promotes microtubule instability. AD patients have an aberrant or hyperphosphorylated tau protein concentration that is four times higher than that of normal controls. These misfolded tau proteins are also recognized as potential neurotoxins and lose their basic function of MT stability along with enhanced aggregation effects.


Sequence and Features


Assembly Compatibility:
  • 10
    COMPATIBLE WITH RFC[10]
  • 12
    COMPATIBLE WITH RFC[12]
  • 21
    COMPATIBLE WITH RFC[21]
  • 23
    COMPATIBLE WITH RFC[23]
  • 25
    INCOMPATIBLE WITH RFC[25]
    Illegal NgoMIV site found at 43
    Illegal AgeI site found at 229
  • 1000
    INCOMPATIBLE WITH RFC[1000]
    Illegal BsaI site found at 207
    Illegal BsaI site found at 1119
    Illegal SapI.rc site found at 393

Dry Lab Characterization

Modeling

The structure of Tau was modeled by several tools and the top model was retrieved from trRosetta ranking 5 out of 6 according to our quality assessment code.


cbeta_deviations molprobity ramachandran_favored ramachandran_outliers Qmean_4 Qmean_6
0 3 95.28 1.05 -1.52844 -2.316739 



                              Figure 1. Predicted 3D structure of Tau(0N4R) modeled by trRosetta


WetLab Results

Tau was expressed in BL21 (DE3) to be purified using affinity chromatography to form aggregates that mimc tau in Alzheimer’s patient’s brain, those aggregates were used later to test the whole system. Tau was purified using affinity chromatography and characterized using BCA and SDS

Transformation of His Tau in DH-5 alpha using pJET cloning vector

Transformation was done using TSS protocol after testing different transformation protocols and optimizing the best conditions for the used protocol with a transformation efficiency = 10000 no. of transformants/ug and CFU/ml = 20000 

                                   Figure 2. Transformed plate of His Tau + pJET.

Transformation of His Tau in BL-21 using pGS-21a expression vector

Transformation was done using TSS protocol after testing different transformation protocols and optimizing the best conditions for the used protocol with a transformation efficiency = 576000 No. of transformants/μg and CFU/ml = 1152000 

                                    Figure 3. Transformed plate of His Tau + pGS-21a.

SDS PAGE of induced and non induced samples of His Tau 

            Figure 4. This figure shows the comparison between the induced and non-induced samples of His Tau, 
            where well no.2 is the non-induced sample while well no.5 is the induced sample showing that our 
            protein is induced effectively owing to our right choice of IPTG, time interval and concentration

Pull down assay of Tau aggregates against GST COH WWW and GST COH TD28Rev 

            Figure 5. This graph shows the comparison of pull down assay between Tau aggregates with GST COH WWW and GST COH 
             TD28Rev, showing that the interaction between Tau aggregates with GST COH WWW is better than that of Tau 
             aggrergates with GST COH TD28Rev as the concentration of elution of Tau aggregates with GST COH WWW is more 
             than that of Tau aggregates with GST COH TD28Rev


References

1 - Iqbal, K., Liu, F., Gong, C. and Grundke-Iqbal, I., 2010. Tau in Alzheimer Disease and Related Tauopathies. Current Alzheimer Research, 7(8), pp.656-664.

2- Muralidar, S., Ambi, S., Sekaran, S., Thirumalai, D. and Palaniappan, B., 2020. Role of tau protein in Alzheimer's disease: The prime pathological player. International Journal of Biological Macromolecules, 163, pp.1599-1617.

3- R. Sajjad, R. Arif, A.A. Shah, I. Manzoor, G. Mustafa Pathogenesis of Alzheimer’s disease: role of amyloid-β and hyperphosphorylated tau protein Indian J. Pharm. Sci., 80 (2018), pp. 581-591, 10.4172/pharmaceutical-sciences.1000397

4- Köpke, E., Tung, Y., Shaikh, S., Alonso, A., Iqbal, K. and Grundke-Iqbal, I., 1993. Microtubule-associated protein tau. Abnormal phosphorylation of a non-paired helical filament pool in Alzheimer disease. Journal of Biological Chemistry, 268(32), pp.24374-24384.

5- Iqbal, K., Gong, C. and Liu, F., 2013. Hyperphosphorylation-Induced Tau Oligomers. Frontiers in Neurology, 4.

6- Gong, C. and Iqbal, K., 2008. Hyperphosphorylation of Microtubule-Associated Protein Tau: A Promising Therapeutic Target for Alzheimer Disease. Current Medicinal Chemistry, 15(23), pp.2321-2328.

7- Alonso, A., Cohen, L., Corbo, C., Morozova, V., ElIdrissi, A., Phillips, G. and Kleiman, F., 2018. Hyperphosphorylation of Tau Associates With Changes in Its Function Beyond Microtubule Stability. Frontiers in Cellular Neuroscience, 12.

8- Pérez, M., Cuadros, R., Smith, M., Perry, G. and Avila, J., 2000. Phosphorylated, but not native, tau protein assembles following reaction with the lipid peroxidation product, 4-hydroxy-2-nonenal. FEBS Letters, 486(3), pp.270-274.

9- Moszczynski, A., Gohar, M., Volkening, K., Leystra-Lantz, C., Strong, W. and Strong, M., 2015. Thr175-phosphorylated tau induces pathologic fibril formation via GSK3β-mediated phosphorylation of Thr231 in vitro. Neurobiology of Aging, 36(3), pp.1590-1599.

10- Lee, H., Perry, G., Moreira, P., Garrett, M., Liu, Q., Zhu, X., Takeda, A., Nunomura, A. and Smith, M., 2005. Tau phosphorylation in Alzheimer's disease: pathogen or protector?. Trends in Molecular Medicine, 11(4), pp.164-169.

11- Chu, D. and Liu, F., 2018. Pathological Changes of Tau Related to Alzheimer’s Disease. ACS Chemical Neuroscience, 10(2), pp.931-944.

12- Lin, Y., Cheng, J., Liang, L., Ko, C., Lo, Y. and Lu, P., 2007. The binding and phosphorylation of Thr231 is critical for Tau’s hyperphosphorylation and functional regulation by glycogen synthase kinase 3β. Journal of Neurochemistry, 103(2), pp.802-813.

13J. Neddens, M. Temmel, S. Flunkert, B. Kerschbaumer, C. Hoeller, T. Loeffler, V. Niederkofler, G. Daum, J. Attems, B. Hutter-Paier

14- Neddens, J., Temmel, M., Flunkert, S., Kerschbaumer, B., Hoeller, C., Loeffler, T., Niederkofler, V., Daum, G., Attems, J. and Hutter-Paier, B., 2018. Phosphorylation of different tau sites during progression of Alzheimer’s disease. Acta Neuropathologica Communications, 6(1).

15- Zhao, H., Chang, R., Che, H., Wang, J., Yang, L., Fang, W., Xia, Y., Li, N., Ma, Q. and Wang, X., 2013. Hyperphosphorylation of tau protein by calpain regulation in retina of Alzheimer's disease transgenic mouse. Neuroscience Letters, 551, pp.12-16.

16- Iqbal, K., Zaidi, T., Wen, G., Grundke-Iqbal, I., Merz, P., Shaikh, S., Wisniewski, H., AlafuzofT, I. and Winblad, B., 1987. Defective brain microtubule assembly in Alzheimer??s disease. Alzheimer Disease & Associated Disorders, 1(3), pp.201-202.

17- Bancher, C., Brunner, C., Lassmann, H., Budka, H., Jellinger, K., Wiche, G., Seitelberger, F., Grundke-Iqbal, I., Iqbal, K. and Wisniewski, H., 1989. Accumulation of abnormally phosphorylated τ precedes the formation of neurofibrillary tangles in Alzheimer's disease. Brain Research, 477(1-2), pp.90-99.

18- Braak, H., Braak, E., Grundke-Iqbal, I., & Iqbal, K. (1986). Occurrence of neuropil threads in the senile human brain and in Alzheimer's disease: A third location of paired helical filaments outside of neurofibrillary tangles and neuritic plaques. Neuroscience Letters, 65(3), 351-355. doi: 10.1016/0304-3940(86)90288-0

19- Rosenmann, H., Blum, D., Kayed, R., & Ittner, L. (2012). Tau Protein: Function and Pathology. International Journal Of Alzheimer's Disease, 2012, 1-2. doi: 10.1155/2012/707482

20- Sierra, H., Cordova, M., Chen, C., & Rajadhyaksha, M. (2015). Confocal Imaging–Guided Laser Ablation of Basal Cell Carcinomas: An Ex Vivo Study. Journal Of Investigative Dermatology, 135(2), 612-615. doi: 10.1038/jid.2014.371

21- Miao, J., Shi, R., Li, L., Chen, F., Zhou, Y., & Tung, Y. et al. (2019). Pathological Tau From Alzheimer’s Brain Induces Site-Specific Hyperphosphorylation and SDS- and Reducing Agent-Resistant Aggregation of Tau in vivo. Frontiers In Aging Neuroscience, 11. doi: 10.3389/fnagi.2019.00034

22- DeTure, M., & Dickson, D. (2019). The neuropathological diagnosis of Alzheimer’s disease. Molecular Neurodegeneration, 14(1). doi: 10.1186/s13024-019-0333-5

23- Uddin, M., Ashraf, G., Mamun, A., & Mathew, B. (2020). Toxic tau: structural origins of tau aggregation in Alzheimer's disease. Neural Regeneration Research, 15(8), 1417. doi: 10.4103/1673-5374.274329