| Summary: | 碩士 === 國立臺灣大學 === 生物科技研究所 === 107 === Telomerase is an enzyme for telomere elongation to protect cells from telomere insufficient, which is composed of telomerase reverse transcriptase (TERT), telomerase RNA component (TERC) and other stabilizing proteins. Mutations of genes that encode telomerase components like TERT or TERC would lead to premature aging and age-related diseases. In human, telomerase haplo-insufficient would cause the telomere syndromes with symptoms of short telomere and mesodermal defects. Several reports demonstrated that telomerase-deficient (Terc-/-) caused the developmental defects in pluripotent stem cells (PSCs), including embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs), evidenced by production of mouse chimeras and tetraploid embryo complementation. The short telomeres also affect differentiation potential of PSCs, especially for mesodermal differentiation. On the other hand, SCR7 and RS-1 are small molecule drugs to stimulate homologous recombination (HR) happened. Telomere also can be elongated by HR in T-loop structure without telomerase participation. We hypothesis that SCR7 and RS-1 might an alternative way to elongate the telomere length and futher rescue the pluripotency of telomerase deficient ESCs. Therefore, by using telomerase- deficient (Terc+/- and Terc-/-) nuclear transfer embryonic stem cells (ntESCs), the aim of this project is to study: 1) whether telomerase-deficient affects mesodermal differentiation potential and 2) whether pluripotency of telomerase-deficient ntESCs can be rescued by SCR7 or RS-1. In our data, although there are not significant difference between Terc+/+, Terc+/- and Terc-/- ntESCs in 10 days of spontaneous differentiation, but the mesodermal defect of Terc-/- ntESCs during the late stage of differentiation process was confirmed by the chondrocyte differentiation. Besides, SCR7 and RS-1 can elongate the telomere length and decrease apoptotic rate of Terc-/- ntESCs during the chondrocyte differentiation. However, the defect of mesodermal differentiation in Terc-/- ntESCs wasn’t rescued by SCR7 or RS-1 treatment. Understanding the mechanism between mesodermal defect and short telomere in telomerase-deficient PSCs and the appropriate way for telomere elongation in telomerase-deficient PSCs would provide insights to how to optimally reset telomeres in patient-specific PSCs especially for telomere syndrome patients.
|
|---|
