Question

GENETICS

1) What are all the types of mutations/Errors found in each of the following: Eukaryotic transcriptional regulation, DNA repair, and inherited mutation in the gene coding region? Be sure to DETAILED everything and provide multiple examples for each of the types of mutations/ errors that goes in each of the mechanisms. Explain specifically how each process could cause illness, for example in humans and other eukaryotic organisms.

It will be awesome if you can provide all the mutations in each mechanisms. Thank you in advance.

Answer 1

Mutation in Eukaryotic Transcription Regulators:

            Transcription factors are proteins that regulate the transcription of genes—that is, their copying into RNA, on the way to making a protein. In humans and other eukaryotes, RNA polymerase can attach to the promoter only with the help of proteins called basal (general) transcription factors. They are part of the cell's core transcription toolkit, needed for the transcription of any gene. There is a large class of transcription factors that control the expression of specific, individual genes. For instance, a transcription factor might activate only a set of genes needed in certain neurons.

Mutation in transcription factor: One or more transcriptional factors are required for a gene express. Some function as gene activators, some others act as inhibitors. They play a great role in feedback mechanism also. Mutation in transcription factor either results in permanent loss of function or permanent gain of function. A loss-of-function mutation results in a gene product (transcription factor) that either does not work or works too little; thus, it can reveal the normal function of the gene. A gain-of-function mutation results in a gene product that works too much, works at the wrong time or place, or works in a new way. Gain of function mutation in transcription promoters and loss of function in transcription inhibitors hugely affects cell cycle machinery, hormone secretion, enzyme actions and can cause dreaded disease like cancer.

Example:

Gene	Function	Cancer Type
GFl 1	Transcriptional Repressor	Medulloblastoma
MYB	Transcriptional factor	Adenoid cystic Carcinoma

Mutation in DNA repair:

            DNA damage is a change in the basic structure of DNA that is not itself replicated when the DNA is replicated. A DNA damage can be a chemical addition or disruption to a base of DNA (creating an abnormal nucleotide or nucleotide fragment) or a break in one or both chains of the DNA strands. When DNA carrying a damaged base is replicated, an incorrect base can often be inserted opposite the site of the damaged base in the complementary strand, and this can become a mutation in the next round of replication. Also DNA double-strand breaks may be repaired by an inaccurate repair process leading to mutations. In addition, a double strand break can cause rearrangements of the chromosome structure (possibly disrupting a gene, or causing a gene to come under abnormal regulatory control), and, if such a change can be passed to successive cell generations, it is also a form of mutation.

            Mutations, however, can be avoided if accurate DNA repair systems recognize DNA damages as abnormal structures, and repair the damages prior to replication.

            If DNA damages in proliferating cells are not repaired due to inadequate expression of a DNA repair gene, this increases the risk of cancer. In contrast, when DNA damages occur in non-proliferating cells and are not repaired due to inadequate expression of a DNA repair gene, the damages can accumulate and cause premature aging.

Example:

BRACA1 and BRACA2 genes normally play a big role in preventing breast cancer. They help repair DNA breaks that can lead to cancer and the uncontrolled growth of tumors. Because of this, the BRCA genes are known as tumor suppressor genes. However, in some people these tumor suppression genes do not work properly. When these genes become altered or broken as a result of mutation, it doesn’t function correctly and causes breast cancer.

Inherited mutation:

The mutations inherited from your parents, are called germ-line mutations. Some well-known inherited genetic disorders include cystic fibrosis, sickle cell anemia, Tay-Sachs disease, phenylketonuria and color-blindness, among many others. All of these disorders are caused by the mutation of a single gene.

            Most inherited genetic diseases are recessive, which means that a person must inherit two copies of the mutated gene to inherit a disorder. This is one reason that marriage between close relatives is discouraged; two genetically similar adults are more likely to give child two copies of a defective gene.

            Diseases caused by just one copy of a defective gene, such as Huntington's disease, are rare. Thanks to natural selection, these dominant genetic diseases tend to get weeded out of populations over time, because afflicted carriers are more likely to die before reproducing.

            Scientists estimate that every one of us has between 5 and 10 potentially deadly mutations in our genes-the good news is that because there's usually only one copy of the bad gene, these diseases don't manifest.