Mitochondrial Ribosomal Protein L3 (MRPL3)

MRPL3 belongs to the L3P ribosomal protein family. A pseudogene corresponding to this gene is found on chromosome 13q. The deduced 349-amino acid protein has a calculated molecular mass of 38 kD. It shares 84% and 62% sequence identity with the rat homolog and the ribosomal protein L3 of E. coli, respectively. Northern blot analysis detected expression of a 1.8-kb transcript in HCC cells at a 3- to 5-fold higher level than that found in normal liver cells. The transcript was expressed at high levels in several other human tumor cells and in fetal and newborn rat livers, and at lower levels in fully differentiated cells. Immunofluorescence staining of hepatoma and HeLa cells indicated localization in nucleoli. MRPL3 was also found in nuclear and ribosomal fractions of HeLa cells, but not in the postribosomal supernatant.