Current Position (2015.1--present)
Associate professor, College of Life Sciences, Beijing Normal University
University of Missouri, Columbia, Missouri, USA
Ph.D in Genetics Area Program / Division of Biological Sciences (2011)
Wuhan University, Wuhan, China
Master in Biosciences / Genetics (2004)
Advisor: Dr. Yi Ding
Wuhan University, Wuhan, China
Bachelor in Biotechnology / Microbiology (2001)
1. The aneuploid as a common phenotype is identified in more than 90% of solid cancer. But it is still unclear what kind of interactions between aneuploid and uncontrolled cell proliferation. Inverse dosage effect, referred as the negative correlation of target gene expressions and chromosome dosage, has been observed in a wide range of aneuploidy in different species, such as maize, Drosophila and some artificial human trisomy cells. To investigate inverse dosage effects and gene dosage compensation in some aneuploidy samples, high throughput RNA-sequencing and relative-quantitative PCR were performed. This effect was suggested as the basic determinant in dosage compensation because of its global effects on gene expressions on the varied and non-varied chromosome segments.
2. Also, the functions of the male specific lethal complex (MSL) were tested through high throughput RNA-sequencing, relative-quantitative PCR and ChIP-seq with certain mutation samples, such as msl3 and mle , in which the complex was destroyed. It was observed that the majority of X chromosome genes were still being compensated even with the absence of this complex, indicating the MSL complex was not required by dosage compensation in Drosophila .
3. The GAL4/UAS system was applied to make transgenic flies with over-expressed protein components of the MSL complex to determine their functions and the mechanism of dosage compensation. The repressive mechanism of the MSL complex in dosage compensation, which was discovered for the first time, was concluded and interpreted that its function is to override the increased level of histone acetylation on the loci of our reporter genes. Meanwhile, the ectopically expressed MSL2 proteins in normal females did not show any ability to induce any up-regulation of the reporter genes. No dosage compensation occurs in those females, even though the functional MSL complex was assembled. From those results, it was concluded that the MSL complex does not directly modulate dosage compensation in Drosophila .
♦ Research Articles
1. Jilong Li, Jia Hou, Lin Sun and et al. , (2015) From Gigabyte to Kilobyte: A Bioinformatics Protocol for Mining Large RNA-Seq Transcriptomics Data. Plos One . 10(4):e0125000.
2. Sun L, Johnson AF, Li J, Lambdin AS, Cheng J & Birchler JA Differential effect of aneuploidy on the X chromosome and genes with sex-biased expression in Drosophila . Proc. Natl. Acad. Sci. USA 110(41):16514-16519.
3. Sun L, Johnson AF, Donohue RC, Li J, Cheng J & Birchler JA (2013) Dosage compensation and inverse effects in triple X metafemales of Drosophila . Proc. Natl. Acad. Sci. USA 110(18):7383-8.
4. Sun L, Fernandez HR, Dohohue RC, Li J, Cheng J & Birchler JA (2012) Male specific lethal complex in Drosophila counteracts histone acetylation and does not mediate dosage compensation. Proc. Natl. Acad. Sci. USA 110(9):E808-17.
College of Life Sciences,
Beijing Normal University,
P. R. China