Telomere-dependent and telomere-independent roles of RAP1 in regulating human stem cell homeostasis

RAP1 is a well-known telomere-binding protein, but its functions in human stem cells have remained unclear. Here we generated RAP1-deficient human embryonic stem cells (hESCs) by using CRISPR/Cas9 technique and obtained RAP1-deficient human mesenchymal stem cells (hMSCs) and neural stem cells (hNSCs) via directed differentiation. In both hMSCs and hNSCs, RAP1 not only negatively regulated telomere length but also acted as a transcriptional regulator of RELN by tuning the methylation status of its gene promoter. RAP1 deficiency enhanced self-renewal and delayed senescence in hMSCs, but not in hNSCs, suggesting complicated lineage-specific effects of RAP1 in adult stem cells. Altogether, these results demonstrate for the first time that RAP1 plays both telomeric and nontelomeric roles in regulating human stem cell homeostasis.

Association between RELN Gene Polymorphisms and Attention Deficit Hyperactivity Disorder in Korean Children

OBJECTIVE: Attention deficit hyperactivity disorder (ADHD) is common disorder of the school-age population. ADHD is familial and genetic studies estimate heritability at 80–90%. The aim of the present study was to investigate the association between the genetic type and alleles for RELNgene (rs736707, rs2229864, rs362746, rs362726, rs362691, rs1062831, rs607755, and rs2072403) in Korean children with ADHD. METHODS: The sample consisted of 180 ADHD children and 159 control children. We diagnosed ADHD according to DSM-IV. ADHD symptoms were evaluated with Conners' Parent Rating Scales and Dupaul Parent ADHD Rating Scales. Blood samples were taken from the 339 subjects, DNA was extracted from blood lymphocytes, and PCR was performed for RELN Polymorphism. Alleles and genotype frequencies were compared using the chi-square test. We compared the allele and genotype frequencies of RELN gene polymorphism in the ADHD and control groups. RESULTS: This study showed that there was a significant correlation among the frequencies of the rs736707 (OR=1.40, 95% CI=1.03–1.90, p=0.031) of alleles of RELN, but the final conclusions are not definite. CONCLUSION: Follow up studies with larger patient or pure subgroups are expected. These results suggested that RELN might be related to ADHD symptoms.

RELN Gene Single Nucleotide Polymorphism Related with Clinical Features of Autism / 中国康复理论与实践

@#Objective To investigate the relationship between RELN gene single nucleotide polymorphism (SNP) and childhood autism in Jiamusi, Heilongjiang. Methods Polymerase chain reaction-restricted fragment length polymorphism (PCR-RFLP) was used to determine allele and genotype of SNP (exon 6) of RELN in 30 children with autism and 30 normal children. Autism Behavior Checklist (ABC) was used to evaluate the children. Results There was a significant difference in the distribution of the allelic frequencies and genotype in exon 6 between these groups (P<0.05). There was a significant difference in the communication factors between patients with genotype of A/A and A/G or A/A and G/G (P<0.05), as well as in the total scores of ABC between A/G and G/G (P<0.05). Conclusion The SNP of RELN (exon 6) associated with the childhood autism. There is a more serious communication disorder in children with genotype of G/G, A/G than that of A/A.