[The relationship between GAPDH mRNA multiple location degradation and advanced stage postmortem intervals].
OBJECTIVE
To study the degradation regularity on different sites of housekeeping gene GAPDH in the same tissue in order to deduce advanced stage postmortem interval (PMI).


METHODS
Rat brain cortex was collected, and 6 sites from 5'-cap to 3'-end in GAPDH mRNA sequence were measured by SYBR Green I real-time RT-PCR to determine the degradation of GAPDH mRNA in brain cortex. Postmortem intervals were extended to 0, 1, 5, 9, 12 days.


RESULTS
All the Ct values of GAPDH mRNA at different sites from the 5'-mRNA cap structure to the 3'-end (GAPDH mRNA 1-GAPDH mRNA 6) in brain correlate with the postmortem periods, while different sites showed different degradation rate. The rates of GAPDH mRNA 4-6 degradation were lower than those of GAPDH mRNA 1-3. If we used GAPDH mRNA 6 as external standard, the ratio of GAPDH mRNA 1-3/GAPDH mRNA 6 were correlated with postmortem periods. However, the relation between GAPDH mRNA 4-5/GAPDH mRNA 6 ratio and postmortem periods were not observed.


CONCLUSIONS
Different sites of housekeeping gene GAPDH in the same tissue share different degradation rates. The degradation of those sites near to 3'-end of mRNA show more precise to deduce advanced stage PMI.
Ren
Guang-Mu
GM
Department of Forensic Pathology, School of Forensic Medicine, Shanxi Medical University, Taiyuan, China.
Wang
Ying-Yuan
YY
Liu
Ji
J
D000818:Animals; D001921:Brain / Q000378:metabolism*; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases / Q000235:genetics / Q000378:metabolism*; D011180:Postmortem Changes; D020871:RNA Stability; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
D012333:RNA, Messenger; D005987:Glyceraldehyde-3-Phosphate Dehydrogenases