instruction:
In this task, you are given an abstract of article. Your task is to generate title for this article. Preferred titles are under thirty words.
question:
The embryonic stem (ES) cell transcriptional and chromatin-modifying networks are critical for self-renewal maintenance. However, it remains unclear whether these networks functionally interact and, if so, what factors mediate such interactions. Here, we show that WD repeat domain 5 (Wdr5), a core member of the mammalian Trithorax (trxG) complex, positively correlates with the undifferentiated state and is a regulator of ES cell self-renewal. We demonstrate that Wdr5, an "effector" of H3K4 methylation, interacts with the pluripotency transcription factor Oct4. Genome-wide protein localization and transcriptome analyses demonstrate overlapping gene regulatory functions between Oct4 and Wdr5. The Oct4-Sox2-Nanog circuitry and trxG cooperate in activating transcription of key self-renewal regulators, and furthermore, Wdr5 expression is required for the efficient formation of induced pluripotent stem (iPS) cells. We propose an integrated model of transcriptional and epigenetic control, mediated by select trxG members, for the maintenance of ES cell self-renewal and somatic cell reprogramming.
answer:
Wdr5 Mediates Self-Renewal and Reprogramming via the Embryonic Stem Cell Core Transcriptional Network

question:
RNA interference (RNAi) is a gene-silencing mechanism by which a ribonucleoprotein complex, the RNA-induced silencing complex (RISC) and a double-stranded (ds) short-interfering RNA (siRNA), targets a complementary mRNA for site-specific cleavage and subsequent degradation. While longer dsRNA are endogenously processed into 21- to 24-nucleotide (nt) siRNAs or miRNAs to induce gene silencing, RNAi studies in human cells typically use synthetic 19- to 20-nt siRNA duplexes with 2-nt overhangs at the 3'-end of both strands. Here, we report that systematic synthesis and analysis of siRNAs with deletions at the passenger and/or guide strand revealed a short RNAi trigger, 16-nt siRNA, which induces potent RNAi in human cells. Our results indicate that the minimal requirement for dsRNA to trigger RNAi is an approximately 42 A A-form helix with approximately 1.5 helical turns. The 16-nt siRNA more effectively knocked down mRNA and protein levels than 19-nt siRNA when targeting the endogenous CDK9 gene, suggesting that 16-nt siRNA is a more potent RNAi trigger. In vitro kinetic analysis of RNA-induced silencing complex (RISC) programmed in HeLa cells indicates that 16-nt siRNA has a higher RISC-loading capacity than 19-nt siRNA. These results suggest that RISC assembly and activation during RNAi does not necessarily require a 19-nt duplex siRNA and that 16-nt duplexes can be designed as more potent triggers to induce RNAi.
answer:
Potent RNAi by short RNA triggers.

question:
Premature chromosome condensation (PCC) was studied in direct preparations of tissues from patients with haematological diseases and carcinomas of various histological types. PCC was found in 6 out of 166 malignancies (128 haematological cases, 35 carcinomas and 3 malignant effusions) analysed with the GTG-technique. Chromosome analysis revealed S-phase and G1-phase PCC in each case; the frequency of PCC varied between 1, 4 and 8.6% of the metaphases analysed. It is suggested that PCC chromosomes, which represent cell fusion in vivo, are not very rare in naturally-occurring human malignancies, and that cell fusion may affect the malignant phenotype. In conjunction with other factors they may also explain the heterogeneity of tumour cell populations.
answer:
Premature chromosome condensation: evidence for in vivo cell fusion in human malignant tumours.