The Central Role Of Transcription Factor Islet-1in The Gene Regulatory Network Of Histone Acetylation During Embryonic Heart Development

OBJECTIVE: To investigate the temporal expression of transcriptionfactor Islet-1and the central role of transcription factor Islet-1in the generegulatory network during the embryonic heart development.METHODS: The whole hearts from newborn mice and embryonicmice on embryonic days11.5(E11.5), E14.5, and E17.5were collectedrespectively. The temporal expression of the transcription factor Islet-1wasquantitative detected by Western-blot method. The relationship betweenIslet-1and histone acetyltransferase was determined using p300/Islet-1primary antibody with co-immunoprecipitation (Co-IP), subsequent massspectrum (MS) analysis, and negative verified by Western-blot assay.Cardiac-special genes, such as GATA4, Mef2c and Tbx5that physicallyinteracted with Islet-1protein, were analyzed using chromatinimmunoprecipitation (Ch-IP) assays and Q-PCR.RESULTS:(1) The data from Western-blot assay revealed that theexpression of the transcription factor Islet-1reached a peak on day E14.5, and then was gradually decreased afterward during embryonic heartdevelopment. The expression of transcription factor Islet-1was significantlyhigher in the group on E14.5(0.434±0.353) than other groups on E11.5(0.074±0.456), E17.5(0.120±0.127) and newborn mice (0.049±0.083)(p<0.05), but there was no significant difference among E11.5, E17.5andnewborn mice (p>0.05).(2) Results from Co-IP、MS and Western-blotassays showed that the transcription factor Islet-1could combine withhistone acetyltransferase p300/GCN5/PCAF and Ac-H3to form complexprotein during the embryonic heart development.(3) Results from Ch-IPassay showed that Islet-1protein physically combined with the promoterregion of cardiac-specific genes (GATA4, Mef2c and Tbx5).CONCLUSION: Islet-1, as a central role, may recruit histoneacetyltransferase p300/GCN5/PCAFand Ac-H3and combine with thepromoter region of cardiac-specific genes (GATA4, Mef2c and Tbx5) duringthe embryonic heart development.