SpRunt1

Function

SpRunt1 is a member of the runt domain family of transcription factors and a positive regulator of the aboral ectoderm-specific CyIIIa gene.
Blots of genomic DNA indicate that SpRunt1 is represented as a single gene per gaploid genome (Coffman J.A. et al.,1996).

Protein

SpRunt1 was initially identifired as the 21-kDa polypeptide (Coffman J.A. et al.,1992), however, conceptual translation of the SpRunt1 cDNA predicted an approximately 60-kDa product, which was verified by in vitro translation (Coffman J.A. et. al.,1996).
Since SpRunt1 appears to be encoded in a single embryonic message, it is likely that the 21-kDa protein represents a proteolytic fragment of the full-length translation product.
DNA-binding activity of the 60-kDa protein resides in the N-terminal half, which includes the runt domain. (Coffman J.A. et. al.,1996).

Subcellular location

Nuclear

Expression Pattern

No maternal SpRunt1 transcripts could be detected.
Transcripts are present in the early embryo at a constant, low level (approximately 700 per embryo) throughout early and late cleavage stages.
After the late blastula stage (24 hr of development) SpRunt1 transcripts rapidly accumulate to an approximately 10-fold higher level.
Thus the SpRunt1 gene is zygotically activated during cleavage, and the later sharp increase in the level of SpRunt1 mRNA depends on further transcriptional activation or/and mRNA stabilization (Coffman J.A. et. al.,1996).

mRNA level

Temporal accumulation (transcripts/embryo)
Method: probe excess titration
Reference: Coffman J.A. et al., 1996

Stage Egg 5h 10h 24h 48h 60h

Level - 0.7*10^3 0.7*10^3 5.7*10^3 6.9*10^3 7.0*10^3