Developmental expression of Apnanos during oogenesis and embryogenesis in the parthenogenetic pea aphid Acyrthosiphon pisum.
Among genes that are preferentially expressed in germ cells, nanos and vasa are the two most conserved germline markers in animals. Both genes are usually expressed in germ cells in the adult gonads, and often also during embryogenesis. Both nanos-first or vasa-first expression patterns have been observed in embryos, implying that the molecular networks governing germline development vary among species. Previously we identified Apvasa, a vasa homologue expressed in germ cells throughout all developmental stages in the parthenogenetic and viviparous pea aphid Acyrthosiphon pisum. In asexual A. pisum, oogenesis is followed by embryogenesis, and both occur within the ovarioles. In order to understand the temporal and spatial distribution of nanos versus vasa during oogenesis and embryogenesis, we isolated a nanos homologue, Apnanos, and studied its expression. In adults, Apnanos is preferentially expressed in the ovaries. In early embryos, Apnanos transcripts are localized to the cytoplasm of cellularizing germ cells, and soon thereafter are restricted to the newly segregated germ cells in the posterior region of the cellularized blastoderm. These results strongly suggest that the Apnanos gene is a germline marker and is involved in germline specification in asexual A. pisum. However, during the middle stages of development, when germline migration occurs, Apnanos is not expressed in the migrating germ cells expressing Apvasa, suggesting that Apnanos is not directly associated with germline migration.
Chang
Chun-Che
CC
Laboratory for Genetics and Development, Department of Entomology, National Taiwan University, Taipei, Taiwan. chunche@ntu.edu.tw
Huang
Ting-Yu
TY
Cook
Charles E
CE
Lin
Gee-Way
GW
Shih
Chun-Liang
CL
Chen
Rita P-Y
RP
D000595:Amino Acid Sequence; D000818:Animals; D001042:Aphids / Q000196:embryology* / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D001483:Base Sequence; D002465:Cell Movement; D005260:Female; D018507:Gene Expression Regulation, Developmental; D005854:Germ Cells / Q000166:cytology / Q000378:metabolism; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D009866:Oogenesis / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics; D016415:Sequence Alignment; D017385:Sequence Homology; D013997:Time Factors
D019476:Insect Proteins; D012333:RNA, Messenger