Coupling astogenic aging in the colonial tunicate Botryllus schlosseri with the stress protein mortalin

Oshrat Ben-Hamo, Amalia Rosner, Claudette Rabinowitz, Matan Oren, Baruch Rinkevich

Research output: Contribution to journalArticlepeer-review


Botryllus schlosseri, a colonial marine invertebrate, exhibits three generations of short-lived astogenic modules that continuously grow and die throughout the colony's entire lifespan, within week-long repeating budding cycles (blastogenesis), each consisting of four stages (A-D). At stage D, aging is followed by the complete absorption of adult modules (zooids) via a massive apoptotic process. Here we studied in Botryllus the protein mortalin (HSP70s member), a molecule largely known for its association with aging and proliferation. In-situ hybridization and qPCR assays reveal that mortalin follows the cyclic pattern of blastogenesis. Colonies at blastogenic stage D display the highest mortalin levels, and young modules exhibit elevated mortalin levels compared to old modules. Manipulations of mortalin with the specific allosteric inhibitor MKT-077 has led to a decrease in the modules’ growth rate and the development of abnormal somatic/germinal morphologies (primarily in vasculature and in organs such as the endostyle, the stomach and gonads). We therefore propose that mortalin plays a significant role in the astogeny and aging of colonial modules in B. schlosseri, by direct involvement in the regulation of blastogenesis.

Original languageEnglish
Pages (from-to)33-46
Number of pages14
JournalDevelopmental Biology
Issue number1
StatePublished - 1 Jan 2018
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2017 Elsevier Inc.


  • Apoptosis
  • Blastogenesis
  • Botryllus schlosseri
  • GRP75
  • HSP70
  • HSPA9
  • PBP74
  • Senescence
  • Stemness
  • Urochordata

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology
  • Developmental Biology


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