nanos-positive germline stem cells of the testes and ovaries (green). (b) WISH showing dmd-1 transcripts in and around (arrows) the testes in a sexually mature planarian.
(c) Ventral view of the animal showing dmd-1 transcripts in the brain (br), sperm ducts (sd), seminal vesicles (sv) and penis papilla (pp) of a sexually mature planarian.
Here we show that a sex-specific gene, Smed-dmd-1 encoding a predicted doublesex/male-abnormal-3 (DM) domain transcription factor, is required for specification of male germ cells in a simultaneous hermaphrodite, the planarian Schmidtea mediterranea.
dmd-1 has a male-specific role in the maintenance and regeneration of the testes and male accessory reproductive organs.
Here, we show that proper development of the hermaphroditic reproductive system in the planarian S.
mediterranea is regulated by a gene encoding a DM domain transcription factor, Smed-dmd-1.
Furthermore, our study of dmd-1 in two flatworm species provides evidence for the conservation of sex regulatory function between lophotrochozoans and other metazoans. 22) of the predicted DM domain protein sequences did not detect significant sequence similarities to other DM domain proteins outside the DM domain, consistent with previous phylogenetic analysis of DM domain genes.
Currently, little is known about how simultaneous hermaphrodites specify and maintain male and female organs in a single individual.
Somatic and germ cells were distinguishable owing to marked differences in the electron density of their cytoplasm and peripheral condensations of heterochromatin in the somatic cells (Fig. The somatic cells seen by TEM likely correspond to dmd-1-expressing cells.
Consistent with this idea, the dmd-1-positive cells in the testes of mature sexual planarians did not express germ cell markers, including nanos, germinal histone H4 (ref.
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