RESUMO
Somatic loss of function mutations in cohesin genes are frequently associated with various cancer types, while cohesin disruption in the germline causes cohesinopathies such as Cornelia-de-Lange syndrome (CdLS). Here, we present the discovery of a recurrent heterozygous RAD21 germline aberration at amino acid position 298 (p.P298S/A) identified in three children with lymphoblastic leukemia or lymphoma in a total dataset of 482 pediatric cancer patients. While RAD21 p.P298S/A did not disrupt the formation of the cohesin complex, it altered RAD21 gene expression, DNA damage response and primary patient fibroblasts showed increased G2/M arrest after irradiation and Mitomycin-C treatment. Subsequent single-cell RNA-sequencing analysis of healthy human bone marrow confirmed the upregulation of distinct cohesin gene patterns during hematopoiesis, highlighting the importance of RAD21 expression within proliferating B- and T-cells. Our clinical and functional data therefore suggest that RAD21 germline variants can predispose to childhood lymphoblastic leukemia or lymphoma without displaying a CdLS phenotype.
Assuntos
Proteínas de Ciclo Celular , Proteínas de Ligação a DNA , Linfoma , Leucemia-Linfoma Linfoblástico de Células Precursoras , Apoptose , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Linhagem Celular Tumoral , Criança , Proteínas de Ligação a DNA/genética , Síndrome de Cornélia de Lange/genética , Pontos de Checagem da Fase G2 do Ciclo Celular , Células Germinativas/metabolismo , Humanos , Linfoma/genética , Mutação , Fenótipo , Leucemia-Linfoma Linfoblástico de Células Precursoras/genéticaRESUMO
The male sex-determining gene, sex-determining region on the Y chromosome (SRY), is expressed in adult testicular germ cells; however, its role in regulating spermatogenesis remains unclear. The role of SRY in the postmeiotic gene expression was investigated by determining the effect of SRY on the promoter of the haploid-specific Protamine 1 (PRM1) gene, which harbors five distinct SRY-binding motifs. In a luciferase reporter assay system, SRY upregulates PRM1 promoter activity in vitro in a dose-dependent manner. Through a gel-shift assay involving a 31-bp DNA fragment encompassing the SRY element within the PRM1 promoter, the third SRY-binding site on the sense strand (-373/-367) was identified as crucial for PRM1 promoter activation. This assay was extended to analyze 9 SRY variants found in the testicular DNA of 44 azoospermia patients. The findings suggest that SRY regulates PRM1 promoter activity by directly binding to its specific motif within the PRM1 promoter.
Assuntos
Testículo , Cromossomo Y , Humanos , Masculino , DNA/metabolismo , Protaminas/genética , Protaminas/metabolismo , Proteína da Região Y Determinante do Sexo/genética , Proteína da Região Y Determinante do Sexo/metabolismo , Testículo/metabolismo , Cromossomo Y/metabolismoRESUMO
A single, rapid and reproducible diagnostic test to predict the type of azoospermia and outcome of sperm retrieval is not yet available. So the feasibility of employing DNA flow cytometry for rapid investigation of the status of spermatogenesis in the patients with azoospermia was investigated. Testicular biopsies of 44 patients with azoospermia undergoing sperm-retrieval surgery and 4 controls were analyzed by flow cytometry to ascertain their testicular germ-cell patterns. The observed germ-cell pattern was further confirmed by RT-PCR analysis of the cell-specific markers and histology for some patients. The patients with Obstructive Azoospermia (OA) exhibited normal spermatogenesis similar to the control fertile patients showing the presence of diploid, double-diploid and haploid cells. The non-obstructive azoospermia (NOA) patients exhibited disrupted spermatogenesis with arrest at the pre-meiotic (only diploid cells present) or meiotic (diploid and double-diploid cells present) stages. The germ-cell pattern, as ascertained by flow cytometry, provided a clear picture of the intra-testicular spermatogenesis and the presence of spermatozoa in the patients' testes, which was prognostic of their sperm-retrieval. DNA flow cytometry test to ascertain the testicular germ-cell pattern is simple in execution, analysis and interpretation, requires small amount of tissue and provides quantitative data about the status of spermatogenesis in patients. This test would allow comparable analysis of the status of spermatogenesis in patients across clinics and may form the basis for deciding future treatment and intervention strategies.