Sex-specific windows for high mRNA expression of DNA methyltransferases 1 and 3A and methyl-CpG-binding domain proteins 2 and 4 in human fetal gonads

DNA methyltransferases (DNMTs) and 5-methyl-CpG-binding domain proteins (MBDs) are involved in the acquisition of parent-specific epigenetic modifications in human male and female germ cells. Reverse Northern blot analyses demonstrated sex-specific differences in mRNA expression for the maintenance DNMT1 and the de novo DNMT3A in developing testis and ovary. In fetal testis DNMT1 and DNMT3A expression peaked in mitotically arrested spermatogonia around 21 weeks gestation. In fetal ovary transcriptional upregulation of DNMT1 and DNMT3A occurred during a very brief period at 16 weeks gestation, when the oocytes proceeded through meiotic prophase. Fetal gonads showed several fold higher DNMT3A…

Microarray mRNA expression analysis of Fanconi anemia fibroblasts.

Fanconi anemia (FA) cells are generally hypersensitive to DNA cross-linking agents, implying that mutations in the different <i>FANC</i> genes cause a similar DNA repair defect(s). By using a customized cDNA microarray chip for DNA repair- and cell cycle-associated genes, we identified three genes, cathepsin B (<i>CTSB</i>), glutaredoxin (<i>GLRX</i>), and polo-like kinase 2 (<i>PLK2</i>), that were misregulated in untreated primary fibroblasts from three unrelated FA-D2 patients, compared to six controls. Quantitative real-time RT PCR was used to validate these results and to study possible molecular links between FA-D2 and other FA subtypes.…

Humans and chimpanzees differ in their cellular response to DNA damage and non-coding sequence elements of DNA repair-associated genes.

Compared to humans, chimpanzees appear to be less susceptible to many types of cancer. Because DNA repair defects lead to accumulation of gene and chromosomal mutations, species differences in DNA repair are one plausible explanation. Here we analyzed the repair kinetics of human and chimpanzee cells after cisplatin treatment and irradiation. Dot blots for the quantification of single-stranded (ss) DNA repair intermediates revealed a biphasic response of human and chimpanzee lymphoblasts to cisplatin-induced damage. The early phase of DNA repair was identical in both species with a peak of ssDNA intermediates at 1 h after DNA damage induction. However, the late phase differed between specie…

CAF-like state in primary skin fibroblasts with constitutional BRCA1 epimutation sheds new light on tumor suppressor deficiency-related changes in healthy tissue

Constitutive epimutations of tumor suppressor genes are increasingly considered as cancer predisposing factors equally to sequence mutations. In light of the emerging role of the microenvironment for cancer predisposition, initiation, and progression, we aimed to characterize the consequences of a BRCA1 epimutation in cells of mesenchymal origin. We performed a comprehensive molecular and cellular comparison of primary dermal fibroblasts taken from a monozygous twin pair discordant for recurrent cancers and BRCA1 epimutation, whose exceptional clinical case we previously reported in this journal. Comparative transcriptome analysis identified differential expression of extracellular matrix-r…

Expression of somatic DNA repair genes in human testes

Meiosis is the key process for recombination and reduction of the diploid chromosome set to a haploid one. Many genes that have been found in yeast or mouse models to play a role in meiosis are also important for the repair of DNA damage in somatic cells. To study the DNA repair gene transcriptome during male germ cell development, we have developed a specialized cDNA microarray with 181 human genes which are involved in different somatic DNA repair pathways and/or cell cycle control and 45 control house-keeping genes. This DNA repair gene chip was used to quantify the mRNA expression levels in three human testes samples versus a fibroblast RNA pool. Two hundred twenty genes on the chip (in…

Searching for Gene Expression Differences in Primary Fibroblasts Between Patients with One and Two Neoplasms in Childhood

Genetic factors are important for developing primary and subsequent malignancies in children. This study investigated the role of genetic factors involved in DNA-repair. Designed as a feasibility study, it addressed the possibility of obtaining samples for genetic analyses from former patients through the German Childhood Cancer Registry. Testing feasibility was as important as the biological question itself. We analyzed the expression of DNA-repair genes in untreated primary fibroblasts of 20 individuals with a second neoplasm compared to 20 matched single neoplasm cases using customized cDNA microarrays (1344 gene sequences, about 800 genes). Matching was by first neoplasm, age, and year …

De-novo Williams–Beuren and inherited Marfan syndromes in a patient with developmental delay and lens dislocation

Abstract 5504: Second neoplasms after childhood cancer and gene expression differences in primary fibroblasts

Abstract Treatment of the primary neoplasm with radiotherapy or chemotherapy is an established risk factor for second neoplasms (SNs) after childhood cancer. As only a small percentage of the treated children suffer from SN, other shared risk factors must be involved. A predisposition for the occurrence of a SN might be a pre-existing somatic genetic defect associated with DNA repair. We investigated the association between gene expression involved in DNA-repair and the development of SNs after childhood cancer. Designed as a feasibility study this project addressed the possibility of obtaining samples for genetic analyses from former patients through the German Childhood Cancer Registry. W…

Homozygous variants in the gene SCAPER cause syndromic intellectual disability

The S-Phase Cyclin A Associated Protein In The ER (SCAPER) gene is a ubiquitously expressed gene with unknown function in the brain. Recently, biallelic SCAPER variants were described in four patients from three families with retinitis pigmentosa (RP) and intellectual disability (ID). Here, we expand the spectrum of pathogenic variants in SCAPER and report on 10 further patients from four families with ID, RP, and additional dysmorphic features carrying homozygous variants in SCAPER. The variants found comprise frameshift, nonsense, and missense variants as well as an intragenic homozygous deletion, which spans SCAPER exons 15 and 16 and introduces a frameshift and a premature stop codon. A…