C. Bierkamp et Ja. Camposortega, A ZEBRAFISH HOMOLOG OF THE DROSOPHILA NEUROGENIC GENE NOTCH AND ITS PATTERN OF TRANSCRIPTION DURING EARLY EMBRYOGENESIS, Mechanisms of development, 43(2-3), 1993, pp. 87-100
We describe here the primary structure of a zebrafish homologue of the
Drosophila neurogenic gene Notch and its pattern of mRNA accumulation
during embryogenesis. The gene produces a 8.5 kb transcript encoding
a putative transmembrane protein with a high degree of sequence simila
rity to members of the Notch family, comprising 36 EGF-like repeats, t
hree lin-12/Notch repeats, six cdc10/SWI6 repeats, OPA repeats and a P
EST sequence. Transcription of the zebrafish Notch gene is spatially a
nd temporally regulated. A high density of transcripts, most probably
of maternal origin, can already be detected in the 2-cell stage. Durin
g pregastrulation stages, RNA is present in all cells. However, follow
ing gastrulation, transcripts accumulate in specific regions of the em
bryo following a rapidly changing pattern. In some of these regions, c
ell divisions take place at the time of Notch expression, in others pr
ocesses of cell differentiation. This holds true for various mesoderma
l derivatives, such as the prospective notochord, and for different ne
ural primordia, such as the neural plate and the brain vesicles. This
pattern of transcript accumulation suggests a role for the zebrafish N
otch homologue in processes of regionalization and cell diversificatio
n.