Insertion of Mutant Lamin Proteins in SW480 colon adenocarcinoma cells Abstract Nuclear Lamina is a mesh like network that lines the nuclear membrane and provides architectural support 2. Lamin proteins are important for cellular structure as well as cellular organization and because of this, functioning lamin proteins are vital in proper expression of genes 1. When mutated, lamin proteins lead to multiple degenerative diseases related to premature aging and diseases like progeria and muscular dystrophy. Although comprehensive research has been done on mutant lamin proteins, the relationship between genotypes and phenotypes are poorly understood 2. This proposal aims to analyze the different genotypic and phenotypic effects by …show more content…
Background and Significance Lamins play an important role in anchoring chromatin to the nuclear periphery. By doing this, the nucleus becomes compartmentalized so the cell is ready for transcription, translation, replication, and repair. Lamin A, lamin C, Lamin B1, and Lamin B2 are the most common lamin proteins. Lamin A and C are known to help with cell survival(willis). Lamin B1 and B2 are known to play a role in organization and survival (http://www.sciencedirect.com/science/article/pii/S1084952113001419). This is important because it organizes the nucleus so that the genes that are going to be expressed are in the middle surrounded by transcription factors (paper he gave us) and the inactive genes are silenced by anchoring it to the periphery of the nucleus. Lamin proteins also help add stability to the nucleus and helps protect it from outside pressure which could damage the replication or transcription process. The more that lamins are expressed, the more mechanically stable the nucleus will be, and tissue rigidity and plasticity. When mutated, Lamin proteins lose their ability to properly organize and provide support for the nucleus. Mutations in lamin proteins lead to over a dozen of degenerative disorders such as muscular dystrophy, peripheral neuropathies, lipodystrophies, and premature aging syndromes (cite). Phenotype-genotype relationships of lamin proteins are poorly understood making it difficult to treat or
Each form has other subtypes, one subtype of LGMD 2 is known as LGMD 2B (dysferlinopathy). In metabolism this disorder is caused by a mutation in the dysferlin Gene (DYSF). According to Keller Metabolism and Proteomic of Limb Girdle Muscular Dystrophy Type 2B (Dysferlinopathy) dysferlin gene is on chromosome 2p13 encoding the 230 kDa protein dysferlin (Keller, 2016). As stated earlier, patients with LGMD show signs of weakness in the muscle more proximal to the body. Affected hip, shoulder and back muscles are physical signs of LGMD that can be seen by Doctors. Dysferlin, which is also known as dystrophy-associated fer-1-like protein; a protein that in humans is encoded by the DYSF gene (Keller, 2016). Dysferlin is correlated with skeletal muscle repair and plays a critical role in the cell repair processes in
Essentially, the nucleus is vital for the cell’s survival. The nucleus controls and gives instructions to all organelles and inhabitants of the cell(Doc. 2). It is a dense, ball shaped configuration that contains the DNA of the cell.
Progeria is an autosomal recessive disease, which means it is not carried on a sex chromosome. Hutchison-Gilford Progeria is caused by a mutation in Lamin A. Lamin A is a fibrous protein involved in the structure of the nuclear membrane. When there is a mutation in Lamin A it is likely the nucleus loses its normal shape and therefore its function is compromised. As of now, it is known that this is the cause of Progeria itself; however, neither doctors nor scientist can determine what this mutation has to do with the aging-like deformities of Progeria (Kugler).
DMD is caused by a mutation in the X-linked dystrophin gene, which results in a dysfunctional dystrophin protein. Dystrophin is a cytoskeletal protein that provides mechanical stability to muscle cells by connecting the muscle sarcolemma to the basal lamina of the extracellular matrix (ECM), and without it there, the muscle cells typically undergo a process of degeneration and regeneration. This process is limited by the survival of satellite cells present since satellite cells can only undergo mitosis a limited amount of times. Sarcolemma instability typically results in excess intracellular amounts of both sodium and calcium, which causes ATP depletion and mitochondrial uncoupling (Horn & Schleip, 2012). Satellite cells only have a limited number times they can undergo mitosis, and once a patient can no longer generate healthy muscle cells, the patient will typically experience cell death. This cell death and necrosis usually
A normal cell will use the genetic information that is found in its DNA, following it’s directions to build proteins. Cells will splice together segments of genetic information, called exons which contain the directions for building proteins. The cells also remove any letters of unused genetic information, called introns. This process is called RNA splicing and it appears to be altered by telomere shortening and this in turn negatively affects the building of proteins that are important in a cell’s cytoskeleton. The cytoskeleton is the internal framework, or scaffolding of a cell, which keeps the cell from collapsing.
Duchenne Muscular Dystrophy is a sex-linked disease, which is inherited in a recessive fashion (National Human Genome Research Institute, 2013). Over thirty similar genetic disorders exist (Duchenne Foundation Australia, 2015). All types of muscular dystrophy are considered to be a rare disorder (Duchenne Foundation Australia, 2015). Duchenne Muscular Dystrophy is most common in children and causes muscle weakness and wasting, which commonly begins in the lower limbs (Duchenne Foundation Australia, 2015; National Human Genome Research Institute, 2013). The disease itself is caused by changes to the DMD gene, which is responsible for providing instructions regarding the creation of the dystrophin protein in one’s muscles (Duchenne Foundation Australia, 2015). This protein is responsible for protecting muscles from damage, and without it the cells of a person’s muscles deteriorate and symptoms of Duchenne Muscular Dystrophy are exhibited (Duchenne Foundation Australia, 2015). The disease results from changes in the DMD gene, or other genetic changes in a child (Duchenne Foundation Australia, 2015).
The LMNA gene was first mapped using in situ hybridization. The gene was detected using clone LA-6, while the hybridization signals were detected using rhodamine-anti-digoxigenin. The samples were analyzed and photographed using a fluorescence microscope. Metaphase figures obtained from the photographs were observed to determine the amount of figures that probed for LMNA. The results showed that 90% of the metaphase figures probed for lamin A/C (Wydner et al. 1996). After analyzing the bands, LMNA was localized to chromosome 1q21.3, giving the chromosomal position of the LMNA gene.
DMD is an X-linked recessive chromosomal that affects 1 in 5,000 males (Yiu and Kornberg). DMD rarely affects females and when they are affected the severity of the disease is much milder than the male cases (Bushby, Finkel and Birnkrant). The mother is the carrier of the DMD gene in 2/3 of cases and can be genetic. The remaining 1/3 of cases are spontaneous mutations that occur in the mother’s egg (Wong, McClaren and Dalton). Males have a 50% chance of inheriting the mutated gene from their mother and presenting with DMD, daughters have 50% chance of inheriting the gene and being a carrier (carriers may not show symptoms but can pass the mutated gene on to their offspring). Fathers cannot pass the gene on to their sons but will pass it on to their daughters (The Muscular Dystrophy Association). The mutation in the DMD gene disrupts dystrophin production. Dystrophin is a protein that is responsible
The malfunction of the protein dystrophin is responsible for the symptoms of DMD. If the dystrophin gene functions correctly, the normal allele codes for the production of the protein dystrophin (“NCBI”). This is a high molecular weight protein, and it is in .002% of the total proteins. Normally, the dystrophin protein functions inside muscle cells, providing structural support. It anchors parts of the internal
Duchenne Muscular Dystrophy is a sex-linked disease, which is inherited in a recessive fashion (National Human Genome Research Institute, 2013). Over thirty similar genetic disorders exist (Duchenne Foundation Australia, 2015). All types of muscular dystrophy are considered to be a rare disorder (Duchenne Foundation Australia, 2015). Duchenne Muscular Dystrophy is most common in children and causes muscle weakness and wasting, which commonly begins in the lower limbs (Duchenne Foundation Australia, 2015; National Human Genome Research Institute, 2013). The disease itself is caused by changes to the DMD gene, which is responsible for providing instructions regarding the creation of the dystrophin protein in one’s muscles (Duchenne Foundation Australia, 2015). This protein is responsible for protecting muscles from damage, and without it the cells of a person’s muscles deteriorate and symptoms of Duchenne Muscular Dystrophy are exhibited (Duchenne Foundation Australia, 2015). The disease results from changes in the DMD gene, or other genetic changes in a child (Duchenne Foundation Australia, 2015).
Med. Genet 2009. 46, 825–833; Cardoso, C., Leventer, R.J., Ward, H.L., Toyo-Oka, K., Chung, J., Gross, A., Martin, C.L., Allanson, J., Pilz, D.T., Olney, A.H., et al. (2003). Refinement of a 400-kb critical region allows genotypic differentiation between isolated lissencephaly, Miller-Dieker syndrome, and other phenotypes secondary to deletions of 17p13.3. Am. J. Hum. Genet. 72, 918–930). MDS is caused by a heterozygous deletion of chromosome 17p13.3, involving several genes including PAFH1B1 and YWHAE coding for LIS1 and 14-3-3 proteins, respectively. This deletion induces malformations during cortical development (Dobyns, W.B., Stratton, R.F., Parke, J.T., Greenberg, F., Nussbaum, R.L., and Ledbetter, D.H. (1983). Miller-Dieker syndrome: Lissencephaly and monosomy 17p. J. Pedod. 102, 552–558; Chong, S.S., Pack, S.D., Roschke, A.V., Tanigami, A., Carrozzo, R., Smith, A.C.M., Dobyns, W.B., and Ledbetter, D.H. (1997). A revision of the lissencephaly and Miller-Dieker syndrome critical regions in chromosome 17p13.3. Hum.
They went to Washington to get money and help from Congress. While there, they got lucky and met Dr. Francis S. Collins and his wife Diane Baker. They agreed to help Sam and his family. They started at Chromosome 1 for answers. Dr. Brown already treated twin boys with troublesome chromosomes. The chromosomes split, turned over, and reattached themselves. This made them find flaws in skin cells. They narrowed it down to a specific spot on the chromosome. Next, they went online to find what genes were in that spot. They realized it was lamin A. This protein can sometimes lead to rare conditions and other problems. The researchers discussed the results together and tested patients. They came to the conclusion that the lamin A was the problem and named the protein progerin. They looked through reports and realized the protein was found in one of Collins’s own patients, Meg Casey. Collins realized she did not have progeria after all. She had mandibuloacral dysplasia
Muscular dystrophy (MD) is a genetic disorder caused by incorrect or missing genetic information that leads to the gradual weakening of the muscle cells. Various causes lead to weak and deteriorating muscles depending on the type of muscular dystrophy the patient was affected by. However, there are many causes for muscular dystrophy due to the fact that there are thirty forms of muscular dystrophy, which are categorized under several categories. All are ultimately caused by autosomal recessive, autosomal dominant, sex-linked, and random mutations in very rare cases.
They are involved because the LMNA gene produces several slightly different proteins called laminas, of the major ones being Lamin A (also known as progerin) and Lamin C. These proteins are generally made throughout the whole body’s cells. The disease is causes the LMNA gene which to become mutated. Althought, this does not causes any harm to lamin c protein, it causes the lamin A protein to misshape, by missing out on 50 amino acids near one end. This is bad because the lamin A protein is a component the nuclear cell membrane. This misshaped version of lamin A is which is responsible for the disorder; it makes it so that it cannot be processed properly in a cell, which then causes a disrupted shape in the nuclear envelope. All in this mutation damages a cell’s structure and function to a nucleus which in turn causes the cells to die
In each form of muscular dystrophy is caused by a genetic mutation particular to that type of the disease. Many of these actions are inherited but, some occur spontaneously