egion; then an action of the chromatin remodeling, it can cause the inhibition on the transcription of the target genes(1) 10. How miRNAs are generated in eukaryotic cells, and how they regulate gene expression? Please list some biological function of miRNAs. (10 points) The miRNA is generated through the pathway described (1)Primary miRNA(Pri-miRNA) is transcribed from the genome of the eukaryotic cells, independently as a mirNa gene or as a part of a mRNA gene in the non-coding region. The pri-miRNA is usually 5'capped and has 3 poly-A tail (2)Pri-miRNA is then processed by Drosha in nucleus, which removes its 5 and 3 end to produce the pre-miRNA(precursor mIRNA) (3)Pre-miRNA is then transported to cytoplasm, where Dicer further process it to the short double helical miRNA of about 21-23 bp The miRNA can regulate gene expression by causing the degradation and/or translational inhibit ion of the homologous mRNAs Biological functions. MiRNAS are involved in animal development, phenotype determination of plants; the differentiation of stem cells, cancer development and probably viral infections. 3(two functions are required) The methods used to produce siRNAs:(nc飞么 11. Do you know how to produce siRNAs? What are ations bile 1)Chemical synthesis 2)In vitro transcription of pre-miRNA with T7 promote 3)In vitro transcription of long dsRna by that is then cleaved by E. coli rNase III or rNase lll-like dicer 4) Transcribed by RNaP Ill in living cells from the transfected DNA plasmid driven by a RNAP Ill promoter such as U6 or HI Applications:(7 points) of th target genes bearing homologous sequence in vivo can be widely applied in biolog ical research and developing new therapeutic treatments the Biological research: siRNA provides a power ful reverse genetics method to study the biological function of an interested gene SIRNA also can be used to perform genome-wide screening of new genes involving in a biological function. Developing new therapeuticS: SiRNA can be used to knock-down the expression of genes from viral pathogens, and of oncogenes causing cancer or other disease-causing genes. Therefore, siRNA provides a powerful approach to combat viral infection and genetic diseases 12. How is the sex determination in fly controlled by the regulation of transcription initiation and alternative splicing?(15 points) A. Early transcriptional regulation of sxl in maile and female fliesregion; then an action of the chromatin remodeling, it can cause the inhibition on the transcription of the target genes (1’). 10. How miRNAs are generated in eukaryotic cells, and how they regulate gene expression? Please list some biological function of miRNAs. (10 points) The miRNA is generated through the pathway described: (1) Primary miRNA (Pri-miRNA) is transcribed from the genome of the eukaryotic cells, independently as a miRNA gene or as a part of a mRNA gene in the non-coding region. The pri-miRNA is usually 5’capped and has a 3’ poly-A tail. 2’ (2) Pri-miRNA is then processed by Drosha in nucleus, which removes its 5’ and 3’ end to produce the pre-miRNA (precursor miRNA). 1’ (3) Pre-miRNA is then transported to cytoplasm, where Dicer further process it to the short double helical miRNA of about 21-23 bp 2’ The miRNA can regulate gene expression by causing the degradation and/or translational inhibition of the homologous mRNAs. 2’ Biological functions. MiRNAs are involved in animal development, phenotype determination of plants; the differentiation of stem cells, cancer development and probably viral infections. 3’ (two functions are required) 11. Do you know how to produce siRNAs? What are the applications of siRNAs in biological research and developing new therapeutics? (10 points) The methods used to produce siRNAs: (3 points) 1) Chemical synthesis 1’ 2) In vitro transcription of pre-miRNA with T7 promoter. 1’ 3) In vitro transcription of long dsRNA by that is then cleaved by E. coli RNase III or RNase III-like Dicer. 1’ 4) Transcribed by RNAP III in living cells from the transfected DNA plasmid driven by a RNAP III promoter such as U6 or H1. 1’ Applications: (7 points) The capability of siRNA in specifically down-regulating the expression of the target genes bearing homologous sequence in vivo can be widely applied in biological research and developing new therapeutic treatments. 1’ Biological research: siRNA provides a powerful reverse genetics method to study the biological function of an interested gene. siRNA also can be used to perform genome-wide screening of new genes involving in a biological function. 3’ Developing new therapeutics: siRNA can be used to knock-down the expression of genes from viral pathogens, and of oncogenes causing cancer or other disease-causing genes. Therefore, siRNA provides a powerful approach to combat viral infection and genetic diseases. 3’ 12. How is the sex determination in fly controlled by the regulation of transcription initiation and alternative splicing? (15 points) A. Early transcriptional regulation of Sxl in maile and female flies: