Discipline: Biological Sciences
Mariah Tolbert - Alabama State University
Co-Author(s): Sheree Finley, Alabama State University, Montgomery, AL; Gulnaz Javan, Alabama State University, Montgomery, AL
Prostate glands are one of the last internal organs to deteriorate during human decomposition; however, this phenomenon is still mysterious. Gene expression in antemortem cases has been widely studied and a majority of the analyses concentrate on discovering basic physiological processes. The question of “What happens to gene expression after a human dies?” is still under investigation. Thanatotranscriptome (thanatos-, Greek for death) involves research on mRNA transcript abundance and gene expression in human tissues after death. Thanatotranscriptome studies are relevant for molecular autopsies due to the potential to provide crucial information to ascertain time of death in medicolegal investigations. Recent scientific breakthroughs have shown that RNA is a suitable and stable molecule in postmortem liver samples up to 48 hours. Accordingly, we hypothesized that there are also measurable and significant differences in mRNA transcript abundances in prostate tissues from homicide and suicide victims. In this study, the goal was to identify apoptotic molecular markers (i.e., pro- and/or anti-apoptosis genes) that provide accurate gene expression profiles regarding the time of death. Tissue samples were removed by a medical examiner from the prostate of five cadavers during autopsy. A control sample with a 24 hrs time of death was also included in the analysis. After RNA extraction, cDNA was synthesized and the concentration was determined. The cDNA was reacted in apoptosis-related gene expression profiling by PCR array in humans to investigate the relationship between time of death and apoptosis gene expression levels. The results of total RNA extraction demonstrated concentrations of greater than 50 ng/μl. Furthermore, the PCR array results show that at 38 hrs after death, a majority of the genes for apoptosis induction and positive regulation (i.e., Caspases) were over-expressed more than at 60 hrs. Some anti-apoptotic genes were also up-regulated at 38 hrs but at 60 hrs, the genes were considerably down-regulated. Therefore, we propose that initially cells counteract programmed cell death with its anti-apoptotic machinery; however, as time progresses, pro-apoptotic mechanisms dominate. In conclusion, our study implies that over-expression of genes in male reproductive organs still occurs after death, which may play critical roles in forensic research (time of death determination) and clinical implications (organ transplantation). Our findings have revealed that there is still active postmortem gene expression; however, our future research question will be “When does gene expression terminate after death?”Not Submitted
Funder Acknowledgement(s): National Science Foundation HRD 1401075
Faculty Advisor: Dr. Gulnaz Javan, firstname.lastname@example.org
Role: In conducting this research I performed i) RNA extraction, ii) cDNA Synthesis, iii)Human Apoptosis PCR Array Analysis, iv) RT2 Profiler PCR Array Data Analysis Version 3.5.