Functional Analysis Of Atac2in The Homeostasis Of Drosophila Intestinal Stem Cells And Generation Of A New Animal Model Of BHD Syndrome

Drosophila is an important model organism in many research fields of life science, likestem cell, animal physiology and disease. This thesis contains the following two parts.1. Identification of Atac2as a novel regulator in the homeostasis of intestinal stem cells.We identified an evolutionary conserved histone acetyltransferase (HAT) Atac2as anovel regulator of the Drosophla intestinal stem cells (ISCs). The main discoveries include:1)Expression of Atac2-RNAi in ISCs results in accelerated cell proliferation and the formationof ISC-like cell clusters;2) Knockdown of some core factors of the ATAC histoneacetyltransferase complex, including Atac2, dGcn5and Ada2a, gave rise to similar ISCphenotypes, indicating Atac2goes through ATAC to control ISC;3) Trichostatin A (TSA) isan inhibitor of class I/II histone deacetylase (HDAC). Feeding flies with TSA promotes ISCdifferentiation and suppresses the effects of Atac2-RNAi, suggesting the HAT function ofAtac2is critical for its function in ISC;4) The putative target of Atac2in ISC is H4K16;5)Amonoclonal antibody against a GST-Atac2fusion protein is obtained.2. Generation of a fly model of the BHD syndrome.The human Birt-Hogg-Dubé (BHD) syndrome is a genetic disorder, which is believed tobe caused by disruption of the FLCN gene. However, its biological functions remain largelyunknown. Using a null allele of the fly FLCN gene as a model (DBHD-/-, developed in ourlab), the following results were obtained:1) DBHD is a vital gene, the DBHD-/-animals diebefore pupation;2) The DBHD-/-larvae grow slowly and display some characteristics ofmalnutrition;3) The growth phenotypes can be rescued by dietary yeast, or a single aminoacid of leucine;4) mTOR is probably a downstream target of DBHD;5)Human Folliculin canrescue the growth defects of DBHD-/-larvae, implying both genes participate in the samephysiological mechanisms.