The following statements were made regarding regulation of aging in C. elegans:A. In most cells, p53 remains bound to a repressor protein to keep it inactive, which is activated under oxidative stress when DNA damage separates p53 from its repressor. B. DAF-2 functions as an insulin-like growth factor receptor to block Forkhead transcription factor and increases the life span. C. When DAF-2 is not active, cells reduce the production of DNA repair enzymes. D. Dietary restriction increases mTORC1 activity, enhancing functional stem cells and longevity.Which one of the following options has the combination of all correct statements?

Correct option is A

Explanation:

A is correct: p53 is usually kept inactive by binding to a repressor protein but is activated in response to oxidative stress or DNA damage to regulate cell cycle and apoptosis.
B is correct: DAF-2 in C. elegans is an insulin/IGF-1 receptor homolog. Its activation inhibits the Forkhead box O (FOXO) transcription factor (DAF-16), thereby reducing lifespan; when DAF-2 is blocked, lifespan increases.
C is incorrect: When DAF-2 is inactive, FOXO/DAF-16 is activated, which increases the expression of genes including DNA repair enzymes, improving longevity.
D is incorrect: Dietary restriction typically decreases mTORC1 activity, which is associated with enhanced longevity and stem cell function; increased mTORC1 promotes aging.

The DAF-2/insulin signaling pathway is a key regulator of aging in C. elegans and many other organisms.
p53 plays a conserved role in DNA damage response and aging.
Reduced mTORC1 activity via dietary restriction mimics caloric restriction effects, promoting lifespan extension.