Conserved expression pattern of chicken DAZL in primordial germ cells and germ-line cells

Abstract

The autosomal gene deleted in azoospermia-like ( DAZL), which was identified as a member of the deleted in azoospermia ( DAZ) family, is homologous to the Drosophila gene BOULE. The authors investigated the sequence similarities of chicken DAZL (cDAZL) with several invertebrate and vertebrate DAZL proteins using CLUSTAL X. A comparison of the primary sequence of cDAZL with other DAZL proteins indicated significant similarities: 70–82% with reptiles, 63–68% with mammals, 51–67% with amphibians, and 42–49% with fishes. The conserved expression pattern of c DAZL was examined by reverse transcription-PCR, quantitative real-time PCR, and in situ hybridization during primordial germ cell (PGC) settlement in the gonads and germ-line development. Among several tissues examined on embryonic day E6.5, DAZL expression was detected specifically in male and female gonads. Quantitative real-time PCR and in situ hybridization revealed strong c DAZL expression in PGCs. When the PGCs differentiated into germ cells, c DAZL expression was slightly decreased; however, expression was continuously detected in germ-line cells until the adult stage. We inferred that c DAZL expression was conserved in PGCs and during germ-line differentiation until the adult stage, making them a valuable molecular marker for studies of PGC differentiation and germ-line development in chickens.