gms | German Medical Science

Objective: The ribosomal protein L37a is a protein that is encoded by the RPL37A gene in humans. Ribosomes are organelles catalyzing protein synthesis. They consist of a large 60S- and a small 40S subunit. Together, these subunits are composed of 4 RNA species and approximately 80 structurally distinct proteins. The RPL37A gene encodes a ribosomal protein that is a component of the 60S subunit. The protein, which is located in the cytoplasm, belongs to the L37AE family of ribosomal proteins. It contains a C4-type zinc finger-like domain. As is typical for genes encoding ribosomal proteins, there are multiple processed pseudogenes of this gene dispersed through the genome. RPL37A is upregulated in high-grade gliomas but downregulated in nasopharyngeal carcinomas. Some studies use it as reference gene in meningiomas.

Method: We used real-time RT-PCR to quantify the expression of RPL37A. MRPL19 and ACTB served as housekeeping genes. We examined a set of about 50 human meningioma samples representing the differences between the three degrees of malignancy (WHO grade I-III), and primary and recurrent meningiomas compared to peritumoral control tissue. We also studied whether the expression profile changes as the same tumor progresses in individual patients. Results are reported as arbitrary units and concentrations between the marker and reference gene mRNA levels. Level of significance was set to 0.05. The results are depicted as mean ± SEM.

Results: The lowest expression level was seen in the control group (1009±158). The expression level increased with higher grade of malignancy (°I tumors: 3039±778, °II tumors: 3887±991, °III tumors: 6131±1298). Furthermore, the expression level decreased in recurrent tumors: °I: 3039 (primary) vs. 2443 (recurrent), °II: 3887 (primary) vs. 2074 (recurrent); °III: 6131 (primary) vs. 3133 (recurrent). The analyzed groups are currently enlarged in order to verify the effect.

Conclusions: RPL37A may not be used as housekeeping gene in meningiomas because it is heavily regulated. The gene was significantly upregulated with degree of malignancy in meningiomas and the expression decreased significantly after chemotherapy. These results provide evidence for an important pathophysiological role of this ribosomal protein. Furthermore, these results could have broad implications for potential targeted therapies.