SIRT1 undergoes alternative splicing in a novel auto-regulatory loop with p53.
PLoS One
; 5(10): e13502, 2010 Oct 21.
Article
in En
| MEDLINE
| ID: mdl-20975832
ABSTRACT
BACKGROUND:
The NAD-dependent deacetylase SIRT1 is a nutrient-sensitive coordinator of stress-tolerance, multiple homeostatic processes and healthspan, while p53 is a stress-responsive transcription factor and our paramount tumour suppressor. Thus, SIRT1-mediated inhibition of p53 has been identified as a key node in the common biology of cancer, metabolism, development and ageing. However, precisely how SIRT1 integrates such diverse processes remains to be elucidated. METHODOLOGY/PRINCIPALFINDINGS:
Here we report that SIRT1 is alternatively spliced in mammals, generating a novel SIRT1 isoform SIRT1-ΔExon8. We show that SIRT1-ΔExon8 is expressed widely throughout normal human and mouse tissues, suggesting evolutionary conservation and critical function. Further studies demonstrate that the SIRT1-ΔExon8 isoform retains minimal deacetylase activity and exhibits distinct stress sensitivity, RNA/protein stability, and protein-protein interactions compared to classical SIRT1-Full-Length (SIRT1-FL). We also identify an auto-regulatory loop whereby SIRT1-ΔExon8 can regulate p53, while in reciprocal p53 can influence SIRT1 splice variation. CONCLUSIONS/SIGNIFICANCE:
We characterize the first alternative isoform of SIRT1 and demonstrate its evolutionary conservation in mammalian tissues. The results also reveal a new level of inter-dependency between p53 and SIRT1, two master regulators of multiple phenomena. Thus, previously-attributed SIRT1 functions may in fact be distributed between SIRT1 isoforms, with important implications for SIRT1 functional studies and the current search for SIRT1-activating therapeutics to combat age-related decline.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Tumor Suppressor Protein p53
/
Alternative Splicing
/
Sirtuin 1
Type of study:
Prognostic_studies
Limits:
Animals
/
Humans
Language:
En
Journal:
PLoS One
Journal subject:
CIENCIA
/
MEDICINA
Year:
2010
Document type:
Article
Affiliation country:
United kingdom