Stage-dependent distribution of calreticulin in oocytes of the frog, Rana rugosa

Masahisa Nakamura*, Kiichirou Kawano, Yasuyuki Kondo, Ikuo Miura, Akihiko Kashiwagi, Satoshi Yamamoto

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


We studied immunohistologically the distribution of a Ca2+-binding protein, calreticulin (CLT), at different stages of growing oocytes in the frog, Rana rugosa. Northern blot analysis showed that the CLT gene expression in gonads of metamorphosing tadpoles was low, but was extremely strong in the ovary, but not in the testis, of 2-month post-metamorphosis frogs, followed by decline to a lower level in adult frogs. On the contrary, the β-actin gene expression did not increase in the same ovary. As for the distribution of CLT protein, a weak immunostaining was observed in indifferent gonads of tadpoles at stage I. The CLT distribution in oocytes from stage A to F was stage-dependent. In addition, Western blot analysis revealed that the CLT level was low in gonads of tadpoles at stage I, but increased at stage XVI. It still increased in the ovary of frogs 2 months after metamorphosis, and then dropped to a lower level in adult frogs. The results indicate that CLT gene expression occurs in the early stage of growing oocytes, and that CLT is synthesized actively in oocytes in the ovary of frogs after metamorphosis. Based on these findings, the role of CLT is discussed.

Original languageEnglish
Pages (from-to)935-940
Number of pages6
JournalZoological Science
Issue number6
Publication statusPublished - 1997 Dec
Externally publishedYes

ASJC Scopus subject areas

  • Animal Science and Zoology


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