China) and quantified by spectrophotometry (NanoDrop ND-1000, Thermo Scientific,
USA). The CDNA was synthesized by RNA, according to the instructions for the use
of manufacturer’s enzymes (Takara, China). One microgram of total RNA was
reacted with a PrimeScript RT Reagent Kit (Takara, China) according to the
manufacturer’s instructions. Quantifications of the target genes Jagged1
(Jag1), delta-like-4 (Dll4), Notch1, hairy and enhancer of split-1 (Hes1), and
mouse atonal homolog 1 (Math1) and a housekeeping gene (GAPDH) in cDNA samples
were carried out by fluorometric real-time PCR using a 7500 fluorescence
detection system (Applied Biosystems, USA) and SYBR-Green PCR kits (Takara,
China). The qPCR thermal cycling conditions were as follows: 5 min at 95
°C, followed by 40 cycles of 15 s at 95 °C and 34 s at 60
°C. All samples were analyzed in triplicate, and the
2−ΔΔCt method was used to analyze gene
expression levels. The fold change value was calculated for a gene expressed in
experimental vs control condition. Primers for specific genes are listed in