||Sea urchin Strongylocentrotus purpuratus
||Howard-Ashby M, Materna SC, Brown CT, Chen L, Cameron RA, Davidson EH. Identification and characterization of homeobox transcription factor genes in Strongylocentrotus purpuratus, and their expression in embryonic development. Dev Biol. 2006 Dec 1 300(1):74-89 p. 82 right column 1st paragraphPubMed ID17055477
||Davidson, E.H., 1986. Gene Activity in Early Development. Academic Press, Inc., Orlando.
||QPCR was used to determine the expression profile of each identified
transcription factor from unfertilized egg to 48 h. mRNA was isolated from egg,
6, 12, 18, 24, 36 and 48 h embryos with the Sigma GenElute Mammalian Total
RNA Miniprep Kit, per the manufacturers instructions.
||Even if only 10
cells were expressing the gene per embryo, all of these rates
are far below the maximal possible rate of gene expression.
This is about 660 molecules/h per cell for any given gene,
assuming that both genomic copies are active (primary source). As observed earlier, low rates of expression are typical
for genes encoding transcription factors (Bolouri and
Davidson, 2003 PMID 12883007).