PCA3 is mostly expressed in LNCaP nucleus and microsomal cell fractions. (A) Total RNA samples obtained from different LNCaP cell compartments. Fraction P1 contained mainly nuclei and some vesicles. Fraction P2 contained nuclei, mitochondria, dense bodies, and vesicles. Fraction P3 contained mainly mitochondria, with a few vesicles and dense bodies. Finally, fraction P4 contained free vesicles and microsomes. Bar graphs represent PCA3 ncRNA relative expression levels in each subcellular compartment, compared to total RNA from LNCAP cell whole extracts, containing a mixture of RNA samples from all cell compartments. 18S rRNA was used as a constitutive gene. (B) Analysis of PCA3 expression by RT-PCR in total RNA samples from primary prostate stromal cell cultures. M: molecular weight marker, 100 bp; Lane 1: Total RNA samples from a single PCa tumor expressing PCA3; Lanes 2 – 4: Three different primary prostate stromal-cell cultures.