Strongylocentrotus purpuratus Genes in Development: Tektin

Tektin B1


Tektin B1 is one of three integral filamentous protein components of outer doublet microtubules. It is synthesized in sea urchins in an amount correlating to the length of embryonic cilia.
The presence of low levels of tektin mRNAs at stages of development prior to ciliogenesis may indicate that the tektins are also involved in other cellular processes such as centriole replication, mitosis and cell division (Norrander et al., 1995).


Tektin B1 is a ~ 47 KDa protein. The tektin A and B polypeptide chains each consist of several alpha-helical coiled-coil regions connected by spans of non-helical linkers (Chen et al., 1993).
GenBank: 3378105

Subcellular location

Expression Pattern

Nothern blotting showed that low levels of tektin B1 mRNA were detected in the unfertilized egg, and there were no changes in message size observed throughout development. Ciliogenesis in this species begins at about 8 hours, after which point there was a marked rise in the level of each tektin mRNA. Post- fertilization levels of tektin B1 and tektin C1 mRNAs were higher than those of tektin A1 mRNA. With respect to peak levels, tektin B1 mRNA increased about 7-fold over post-fertilization levels.
The message level fell rapidly after hatching, however the postciliogenesis level were somewhat higher than those seen in the early cleavage stages (Norrander et al., 1995).
Tektins form filamentous polymers in the walls of ciliary and flagellar microtubules. The organization of tektins in microtubules is not known in detail, but tektins probably interact directly with tubulin.
Immunofluorescence microscopy has demonstrated that tektins A1, B1 and C1 are present in all nine flagellar doublet microtubules and possibly in the central pair microtubules (Steffen and Linck, 1988).

mRNA level

Temporal accumulation *

Method: Nothern blot analysis
Reference: Norrander et al., 1995

Unfertilized egg
3 hours
8 hours
12.5 hours (blastula)
16 h 50 min (rotating blastula)
18.75 hours (hatched, swimming blastula)
19 hours
24 h 50 min (mid-gastrula)

* The autoradiograms were quantitated densitometrically, normalizing mRNA band with corresponding ubiquitin signal.

Ectopic expression

Action of animalizing agents

To determine if tektin mRNA levels were increased in embryos deploying cilia of increased ciliary length, normal embryos were compared with zinc-animalized embryos.
At the period of ciliogenesis, when the tektin mRNA reached a peak, the levels of tektin B1 mRNA were measured in normal and animalized embryos. During this period, ciliary elongation was essentially linear and the level of tektin B1 mRNA remained relatively constant.
In the case of zinc-treated embryos the tektin B1 mRNA was up-regulated and its level increased 2.2 times (ubiquitin and tubulin levels increased 2.3 and ~2-fold respectively). These levels do not correlate with the 1/3 ciliary length increase (Norrander et al., 1995).



Regulatory Regions

Regulatory Connections

Upstream Genes

Tektin B1

Downstream Genes

Evolutionary Homologues



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