Expression of Normal or Mutated X-Linked BCOR Transcripts in OFCD iPSCs.

Reprogramming diseased cells with mutated genes into induced pluripotent stem cells (iPSCs) can allow studies of disease mechanism and correct the mutation. Oculofaciocardiodental (OFCD) syndrome is a developmental disorder caused by heterozygous mutations in the X-linked BCL-6 corepressor (BCOR) gene. In this present study, we aimed to reprogram stem cells from a tooth apical papilla (SCAP) of a patient with OFCD, termed SCAP-O, into iPSCs. The SCAP-O carry a copy of the BCOR gene having 1 nucleotide deletion in 1 of the alleles, therefore harboring a mixture of cells expressing either normal (SCAP-OBCOR-WT) or mutated (SCAP-OBCOR-mut) BCOR transcripts. We subcloned SCAP-O and separated SCAP-OBCOR-WT and SCAP-OBCOR-mut as verified by sequencing. The selected subclone SCAP-OBCOR-mut expressed only the mutated BCOR transcripts and remained in such condition after multiple passages. We reprogrammed SCAP-O and subclone SCAP-OBCOR-mut into transgene-free iPSCs using an excisable lentiviral vector system (hSTEMCCA-loxP) carrying 4 reprogramming factors in a single cassette, followed by removal of transgenes via Cre-mediated excision. We found that after reprogramming SCAP-O or subclone SCAP-OBCOR-mut into iPSCs, some of the iPSC clones expressed either solely the normal BCOR-WT or BCOR-mut transcripts, while other clones expressed both BCOR-WT and BCOR-mut transcripts. This is our first step toward establishing OFCD study models by generating isogenic control BCOR-WT iPSCs versus BCOR-mut iPSCs.

KIAA0510, the 3'-untranslated region of the tenascin-R gene, and tenascin-R are overexpressed in pilocytic astrocytomas.

AIMS: Studying the molecules and signalling pathways regulating glioma invasiveness is a major challenge because these processes determine malignancy, progression, relapse and prognosis. We took advantage of our previous study focused on genes that were critical in tumour invasion to further study here an unknown sequence, referred to as KIAA0510, the chromosomal location of which was 1q25, described as a 5596-bp long mRNA and that we found to be significantly overexpressed in pilocytic astrocytomas compared with glioblastomas. METHODS AND RESULTS: Using in silico analysis as well as Polymerase chain reaction techniques, we decipher the full genomic characterization of the KIAA0510 sequence and demonstrate that KIAA0510 constitutes the 3'-untranslated region of tenascin-R gene. We have clearly confirmed the overexpression of tenascin-R in pilocytic astrocytomas vs. glioblastomas at mRNA and protein levels. We also analysed a large series of various brain tumours and found that in the group of astrocytic tumours, tenascin-R expression decreased with malignancy, whereas oligodendrogliomas sometimes retained a high level of tenascin-R even in high-grade tumours. Gangliogliomas strongly expressed tenascin-R too. In contrast, ependymomas and meningiomas were negative. In normal brain, tenascin-R was exclusively expressed by normal oligodendrocytes and subsets of neurones during post-natal development and in adulthood, where it could differentially affect cellular adhesiveness and/or differentiation. CONCLUSION: KIAA0510, the 3'-untranslated region of the tenascin-R gene, and tenascin-R are overexpressed in pilocytic astrocytomas. Gangliogliomas shared with pilocytic astrocytomas strong tenascin-R expression. Whether tenascin-R overexpression negatively influences brain invasion remains to be determined.