Question

Retinoblastoma (resulting in eye tumor) results from inactivation of Rb gene, a tumor suppressor.

A).List the molecular events that lead to the development of hereditary retinoblastoma?

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B). How the development of sporadic retinoblastoma will be different from the hereditary one? Mention the molecular steps that will be unique for the sporadic retinoblastoma?

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C). Is the loss of Rb function dominant or recessive and why?

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D). Knowing the Rb binds to E2F, which is transcription factor activating expression of proteins involved in DNA replication, predict the cellular events (on DNA level) that will be initiated following the loss of RB. Why these events will lead to cancer (write step by step what will happen in the cell following the loss of RB and result in cancer). Explain your answers.

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Answer 1

A) the hereditary retinoblastoma occurs due to the the changes in the RB1 gene the role og RB1 gene is to tell the body cell's how to perform a function .it control the growth and division of the cell. the RB1 prevents from the tumor .in the normal cell contain two copies of RB1 .in the hereditary retinoblastoma the patient carry one workingRB1 gene and one altered RB1 gene meant one copy is mutated ,the deletion of genetic material from the 13 chromsomes which contain the other gene and RB1 gene .due to this mutation the working copy becomes damaged within a cell of the developing retina ,which lead to the retinoblastoma.

B) the sporadic retinoblastoma do not pass into the families. the sporadic retinoblastoma occurs due to the maternal health effect. the use of drugs during the pregnancy.

c) the RB1 gene show  an autosomal dominant inheritance . one copy of mutated gene is enough for the increase the risk of cancer .

e) the mechanism of RB1 protein

E2 F ATP Cuclim cdk RBL mitosis Cel pucem

the mutant form of RB1 gene cannot dissociate from the E2F which affect the cell cycle.