Post-transcriptional Regulation of BRCA2 through Interactions with miR-19a and miR-19b.

Breast cancer type 2, early onset susceptibility gene (BRCA2) is a major component of the homologous recombination DNA repair pathway. It acts as a tumor suppressor whose function is often lost in cancers. Patients with specific mutations in the BRCA2 gene often display discrete clinical, histopathological, and molecular features. However, a subset of sporadic cancers has wild type BRCA2 and display defects in the homology-directed repair pathway, which is the hallmark of 'BRCAness.' The mechanisms by which BRCAness arises are not well understood but post-transcriptional regulation of BRCA2 gene expression by microRNAs (miRNAs) may contribute to this phenotype. Here, we examine the post-transcriptional effects that some members of the six-miRNA cluster known as the miR-17/92 cluster have on the abundance of BRCA2's messenger RNA (mRNA) and protein. We discuss two interactions involving the miR-19a and miR-19b members of the cluster and the 3'UTR of BRCA2's mRNA. We investigated these miRNA:mRNA interactions in 15 cell lines derived from pancreatic, breast, colon, and kidney tissue. We show that over-expression of these two miRNAs results in a concomitant decrease of BRCA2's mRNA and protein expression in a subset of the tested cell lines. Additionally, using luciferase reporter assays we identified direct interactions between miR-19a/miR-19b and a miRNA response element (MRE) in BRCA2's 3'UTR. Our results suggest that BRCA2 is subject to a complex post-transcriptional regulatory program that has specific dependencies on the genetic and phenotypic background of cell types.

Comparison of Western immunoblotting and the C6 Lyme antibody test for laboratory detection of Lyme disease.

Three commercial Lyme disease Western immunoblotting (WB) kits and the C6 Borrelia burgdorferi (Lyme) enzyme-linked immunosorbent assay (ELISA) kit were compared using two commercially available performance panels from the Centers for Disease Control and Prevention (CDC) and Boston Biomedica (BBI). Combined, the panels consisted of 52 characterized specimens. Immunoglobulin G (IgG) sensitivity was similar for the three WB products. The BBI and Marblot WBs were more specific for IgG antibodies, while the Virablot was the most sensitive for IgM antibody. The BBI WB was 100% specific for IgM, while Marblot was 97% and Virablot was 77% specific for IgM. The C6 ELISA was found to be 100% sensitive. Four false-positive C6 results were identified in patients that had clinically and microbiologically confirmed Lyme disease but were not detected by the CDC reference methods. No one WB product showed overall superiority. The C6 ELISA shows promise as the first ELISA for Lyme disease that would not require a supplemental test such as a WB.