This ancestral population includes both cells expressing Cer1 together with cells in which Cer1 expression begins after implantation and formation of the AVE [ 60].
During optic cup formation Raldh2 is first expressed transiently in perioptic mesenchyme, then later Raldh1 and Raldh3 expression begins in the dorsal and ventral retina, respectively, and these sources of retinoic acid are maintained in the fetus.
The time points of embryonic day 18.5 and postnatal day 30.5 were selected as the period in which Nr2e3 expression begins, and as an adult time point in which Nr2e3 is expressed.
In this context his curious method of expression begins to make sense.
In particular, OsCOL4 expression is maintained at a high level in the early vegetative stages but decreases when Ehd1 expression begins (Lee et al. [2010]).
While its expression begins when the meiosis starts about 2 h after the initiation of conjugation and remains high till the end of meiosis II, suggesting its probable role in meiosis process (Miao et al., 2009).
Insulin gene expression begins early in the embryonic development of the pancreas and remains tightly-regulated throughout adult life.
GFP expression begins within the first week of cell division and disappears as newborn neurons mature, about 4 weeks postmitotic.
In ovaries, expression begins in stage 3 germaria, at which time premieiotic mitoses have created the 16-cell cyst, and persists through individualized follicles.
Expression begins during early planula stages on the left and right sides of the directive axis in body wall endoderm (Figure 4M and 4N).
Similarly, Dio2 (TH-activating enyzme) expression begins within this Cyp26 domain, but is excluded from the presumptive central rod-free zone and primarily expands only ventrally (Fig. 13B).
