Correlation between RNA Expression Level and Early PMI in Human Brain Tissue / 法医学杂志

OBJECTIVES@#To explore the correlation between the expression levels of several RNA markers in human brain tissue and early postmortem interval （PMI）.@*METHODS@#Twelve individuals with known PMI （range from 4.3 to 22.5 h） were selected and total RNA was extracted from brain tissue. Eight commonly used RNA markers were chosen including β-actin, GAPDH, RPS29, 18S rRNA, 5S rRNA, U6 snRNA, miRNA-9 and miRNA-125b, and the expression levels were detected in brain tissue by real-time fluorescent quantitative PCR. The internal reference markers with stable expression in early PMI were screened using geNorm software and the relationship between its expression level and some relevant factors such as age, gender and cause of death were analyzed. RNA markers normalized by internal reference were inserted into the mathematic model established by previous research for PMI estimation using R software. Model quality was judged by the error rate calculated with estimated PMI.@*RESULTS@#5S rRNA, miRNA-9 and miRNA-125b showed quite stable expression and their expression levels had no relation with age, gender and cause of death. The error rate of estimated PMI using β-actin was 24.6%, while GAPDH was 41.0%.@*CONCLUSIONS@#5S rRNA, miRNA-9 and miRNA-125b are suitable as internal reference markers of human brain tissue owing to their stable expression in early PMI. The expression level of β-actin correlates well with PMI, which can be used as an additional index for early PMI estimation.

Molecular analysis of snRNAs and scRNAs using autoantibodies from patients with systemic lupus erythematosus

Immunoprecipitation analysis of total HeLa cells RNA extract byprotein A-Sheparose purified autoantibodies and pCp 32P-3' end labeling RNAs revealed that U1, U2, U4 and U5 snRNAs are related with anti-Sm or U1nRNP autoantibodies, while the hY1, hY3, hY4 and hY5 scRNAs were related to anti-SSA/Ro autoantibodies present in sera of patient with Systemic Lupus Erythematosus. The authors detected molecular snRNAs and scRNAs specificities by autoantibodies in 71 sera, the molecular RNA specificity for anti-Sm (U1, U2, U4 and U5 snRNAs) was present in 39 percent; anti-SSA/Ro sera reacted against scRNAs (hY1, hY3, hY4 and hY5) in 36 percent, then anti-U1nRNP sera recognized U1 snRNA in 13 percent of sera and anti-rRNP related with rRNA were recognized in 8 percent. Twenty-nine SLE sera were RNA negative. A molecular characterization of the autoantibodies in sera from SLE patients may be a useful tool for clinical and laboratory diagnosis of SLE, and the use of autoantibodies es molecular probes allows to continue exploring some basic mechanism of gene expression