| Abstrakt: |
To investigate the germ cell specification in urodeles, we cloned aDAZ-likesequence from the Japanese newtCynops pyrrhogaster,Cydazl, and raised antibodies specific to Cydazl.Cydazlis a homologue of the humanDAZ(deleted in azoospermia),DAZL, andXenopus dazlgenes, which are involved in gametogenesis or germ cell specification. During gametogenesis, expression ofCydazlmRNA and Cydazl protein was detected at first in the small previtellogenic oocytes in females but was not localized as seen inXenopusand was restricted to secondary spermatogonia prior to meiosis in males. During early embryogenesis, maternal stores of theCydazltranscript and protein were present in the entire embryos, not localized in any specific region. The zygotic expression was detected in hatching larvae (stage 50) by RT-PCR analysis whereas specific cells expressingCydazlcould not be determined by in situ hybridization at this stage. Strong expression ofCydazland Cydazl were detected in primordial germ cells (PGCs) that had entered the gonadal rudiment at late stage 59. These results suggest thatCydazldoes not function early in development, for the specification of germ cells, but functions later for differentiation of germ cells in the developing gonads during embryogenesis and for meiotic regulation, supporting the previous idea of an intermediate germ cell formation mode in urodeles. [ABSTRACT FROM AUTHOR] |
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