DNA methylation is widespread in most species, from bacteria to mammals, and is 
crucial for genomic imprinting, gene expression, and embryogenesis. DNA 
methylation occurs via two major classes of enzymatic reactions: 
maintenance-type methylation catalyzed by DNA (cytosine-5-)-methyltransferase 
(DNMT) 1, and de novo methylation catalyzed by DNMT 3 alpha (DNMT3A) and -beta 
(DNMT3B). The expression pattern and regulation of DNMT genes in primordial germ 
cells (PGCs) and germ line cells has not been sufficiently established in birds. 
Therefore, we employed bioinformatics, RT-PCR, real-time PCR, and in situ 
hybridization analyses to examine the structural conservation and conserved 
expression patterns of chicken DNMT family genes. We further examined the 
regulation of a candidate de novo DNA methyltransferase gene, cDNMT3B by 
cotransfection of cDNMT3B 3'UTR- and cDNMT3B 3'UTR-specific miRNAs through a 
dual fluorescence reporter assay. All cDNMT family members were differentially 
detected during early embryonic development. Of interest, cDNMT3B expression was 
highly detected in early embryos and in PGCs. During germ line development and 
sexual maturation, cDNMT3B expression was reestablished in a female germ 
cell-specific manner. In the dual fluorescence reporter assay, cDNMT3B 
expression was significantly downregulated by four miRNAs: gga-miR-15c (25.82%), 
gga-miR-29b (30.01%), gga-miR-383 (30.0%), and gga-miR-222 (31.28%). Our data 
highlight the structural conservation and conserved expression patterns of 
chicken DNMTs. The miRNAs investigated in this study may induce downregulation 
of gene expression in chicken PGCs and germ cells.