Strongylocentrotus purpuratus Genes in Development:
Tyrosine Kinases
WEE1S.purp
Function
WeeI-like kinases act as negative regulators
of mitosis by inactivating cyclin-dependent kinases (CDK) (Nemer and Stuebing, 1996).
Protein
WEE1S.purp
encodes a 624 amino acid polypeptide (WEE1S.purp) with a
high degree of similarity to the Mik1 and Wee1 protein
tyrosine kinases.
The N-terminal domain of the predicted WEE1S.purp
polypeptide is enriched in S/TP-containing, potential
kinase-target sites, as well as high-value "PEST'
sequences, associated with protein lability (Nemer and Stuebing, 1996).
GenBank: 1171350
Subcellular location
Expression Pattern
Nothern blot analyses of total embryonic RNA revealed
a 4.5-kb WEE1S.purp transcript.
Measurements of WEE1S.purp RNA concentration
showed that the amount in egg and for the first 7-8 hr of development,
was close to the limit of detection; however, transcripts began
to accumulate at the 8-h early blastula stage, between
the fifth and the sixth cell cycle, and reached a maximum level
of 2.5*104 transcripts/embryo in the 16-20 h
mid-blastula.
At the 12-hr early blastula Nothern blots of total RNA
indicated the presence of 1*104 transcripts per embryo.
Only a faint band was detected in the egg RNA, suggesting
an upper limit of no more than 1*103 transcripts
per egg.
Thus, WEE1S.purp mRNA accumulation is initiated
between the fifth and sixth cell cycles and displays a maximal rate
between the seventh and eighth cell cycles.
The uniform expression observed by the whole mount in situ
hybridization in the blastula changes in the later stage embryo
to a localization in the endoderm (gut) and oral ectoderm.
At various pluteus larval stages, WEE1S.purp mRNA
is distributed to different degrees between the regions of the
gut and the oral ectoderm, and is never detected in the aboral
ectoderm.
In plutei WEE1S.purp mRNA can be seen to extend from the oral ridge
out to the arm rudiments. WEE1S.purp mRNA appeares first in the arm
rudiments (at 64 h) and in the elongating post oral arms (at 72 h).
However, by the 92nd hour, when elongation has ceased, the mRNA is
no longer detectable in arms. This limitation of WEE1S.purp mRNA expression
to proliferating cells is another example of its linkage to cycling
cells (Nemer and Stuebing, 1996).
mRNA level
Temporal accumulation
Method: Nothern blot analysis
Reference: Nemer and Stuebing, 1996
Stage
Egg
2 hr
4 hr
8 hr
10 hr
12 hr
14 hr
16 hr
18 hr
20 hr
24 hr
28 hr
32 hr
Level
+ -
+ -
+ -
+ -
+ -
+
+
+ +
+ +
+ +
+
+
+ -
Spatial localization
Method: Whole mount in situ hybridization
Reference: Nemer and Stuebing, 1996
Stage
Blastula
Mid-gastrula
64-hr pluteus larva
72-hr pluteus larva
92-hr pluteus larva
Tissue
all cells
endoderm (gut),
oral ectoderm
endoderm (gut),
oral ectoderm, arm rudiments
endoderm (gut),
oral ectoderm, elongating post oral arms
endoderm (gut),
oral ectoderm, is no longer detectable in arms
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