It is quite common for Hox genes to be expressed in multiple germ layers in the Bilateria.
Like other organs, vertebrate appendages are composed of complex tissues that originate from multiple germ layers.
Interestingly, synchronous or metachronous development of multiple germ cell tumours in the same patient insinuates an underlying common pathogenetic mechanism concerning genetic instability or abnormalities during the pluripotent embryonic germ cell differentiation and maturation.
In these cases of multiple germ cell tumours, strong theoretical and clinical data suggest an underlying common pathogenetic mechanism concerning genetic instability or abnormalities during the pluripotent embryonic differentiation and maturation of the germ cell.
These include multiple germ cell-specific isozymes with novel N-terminal extensions that are hypothesized to play a role in localizing glycolysis in the principal piece, thereby insuring an adequate supply of ATP along the full length of the flagellum.
Third, we noted that at the single-cell level, a single Oct4-GFP+ cell following differentiation was more likely to express multiple germ cell marker transcripts in the same cell than an undifferentiated GFP+ ESC.
To assess whether this coat colour contribution was indicative of high overall contribution of ES-derived cells to multiple germ layers, we examined the contribution of GFP-positive cells to organs and tissues of two chimaeras.
The contribution of multiple germ line V H, D and J H gene segments to antibody diversity is magnified by the random rearrangement of these segments in somatic cells [ 14].
Importantly, this suggests that bovine derived-UC-WJ cells are capable of differentiation into multiple germ layers, an essential characteristic also observed in porcines, dogs, horses, duck and avian species [ 15- 17, 24- 27, 29- 33].
In direct contrast, testes transplanted with undifferentiated H9 (Fig. 4Av) and H1 (Fig. 4Aiii) hESCs, developed enlarged tissues indicative of tumors similar to OSKM cells (Fig. 4Aii) and in addition formed teratoma-like structures (in H9 cells only, Fig. 4Avi) indicative of multiple germ layer tissue formation (see also Supplementary Material, Table S3).
