Overview of Molecular Biology

While the members of the FA complementation group do not share sequence similarity, they are related by their assembly into a common nuclear protein complex. Beside these sixteen FA proteins, there are several other proteins associating with the FA core complex, known as the FA Associated Proteins (FAAPs): -100, -24, -20, -16/MHF1, and -10/MHF2. FA plays an important role in the genomic stability through DNA repair of interstrand crosslinks (ICLs). When mutations occur in these genes, however, abnormal cell division, which eventually causes cancer and congenital defects occurs in most patients (Nalepa, et al., 2013; Tomida, et al., 2013). Fanconi anemia is caused by mutations in one of the Fanconi anemia genes leading to lack of interstrand crosslink repair.

Selby CP, Drapkin R, Reinberg D, Sancar A (1997) RNA polymerase II stalled at a thymine dimer: footprint and effect on excision repair. Nucleic Acids Res 25:787-793. Tornaletti S, Maeda LS, Hanawalt PC (2006) Transcription Arrest at an Abasic Site in the Transcribed Strand of Template DNA. Chemical Research in Toxicology 19:1215-1220.

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Nature 460, 1132-1135. Lee, S., Elenbaas, B., Levine, A.J, and Griffith, J., 1995. p53 and its 14 kDa C-terminal domain recognize primary DNA damage in the form of insertion/deletion mismatches. Cell 81, 1013-1020. Levine, A.J., 1997. p53, the cellular gatekeeper for growth and division. Cell.

Genetic testing is becoming more and more common as advancements in biotechnology are being made. The term “genetic testing” refers to the use of a test that looks for changes in a person’s genes or structure of certain proteins (National Human Genome Research Institute [NHGRI], 2014). Genes are decoded and each letter of the DNA sequence can be determined. There are many uses for this type of testing, including, but not limited to, diagnosis of rare genetic disorders, risk analysis for hereditary diseases, and determining appropriate treatments for patients. There are three types of genetic tests: gene tests, which look at fairly short lengths of DNA or RNA, chromosomal tests, which examine whole chromosomes, and biochemical tests, which test protein levels and/or enzyme activities (NHGRI, 2014).

This forms a complex which blocks translation via the binding to mRNA, (Phillips ,Theresa) miRNAs are able to target up to several hundred genes through binding to different regions and imperfect base pairing. (Larson, Richard A) miRNAs are a class of non-coding RNAs that regulate the expression of genes by binding to complementary regions; this is done commonly with the 3’UTR of target mRNA resulting in mRNA degradation and translational repression.(Goodal). Bound to an argonaute protein all miRNAs require this for miRNA function( Nilsen, Timothy W. Gene regulation is the process of turning on and off the genes in our cells as they are required. This is needed as every cell in our bodies has a complete set of the genome, and the difference between cells is what genes are being expressed and not expressed within them. The differentiation between cells is due to different regulatory elements.

It also codes for the catalytic subunits of the mitochondrial DNA polymerase (Genetic Home Reference : Your Guide to Understanding Genetic Conditions, 2014). Alpers disease is a DNA polymerase (this is needed for POLG function) related disorder and it is caused by a mutation in the DNA polymerase, it is a biochemical defect. DNA polymerase is an enzyme that reads sequences of DNA. It is also responsible for coping and replicating cells genetic contents. Along with reading and replicating DNA polymerse also plays an important part in DNA repair.

Other NER substrates include bulky chemical adducts, DNA intrastrand crosslinks, and some forms of oxidative damage. Two distinct NER pathways exist: transcription-coupled NER which focuses on lesion blocking transcriptions and global genome NER which surveys the entire genome for distorting damage (Jackson and Bartek, 2009, David et al., 2007 ). DNA mismatch repair (MMR) pathway plays an essential role in the correc... ... middle of paper ... ...ing proteins. The large protein kinase, consisting of 4128 amino acids (aa), has a molecular weight of 469 kDA (33, 85-87). DNA-PKcs associates with the Ku70/80 heterodimer and forms a catalytic active DNA-PK holoenzyme (Falck et al., 2005).

and Caskey, C.T. Trinucleotide repeat disorders in humans: discussions of mechanisms and medical issues. FASEB J. 1996; 10: 1589-1597. Wells, R.  Molecular basis of genetic instability of triplet repeats.

Nature Education 14) Man P Y W, Turnbull D M, Chinnery P F (2002) Leber hereditary optic neuropathy. J Med Genet 39, 162-169. 15) Taylor R W, Turnbull D M. (2005) Mitochondrial DNA Mutations in Human Disease, Nat Rev Genet. 389-402.