Spz1, a novel bHLH-Zip protein, is specifically expressed in testis

Shih Hsien Hsu, Huey Wen Shyu, Hsiu Mei Hsieh-Li, Hung Li*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

36 Citations (Scopus)


We isolated a novel bHLH-Zip gene designated Spz1 from a mouse testis cDNA library. Spz1 is expressed specifically in the testis and epididymis. Immunofluorescence staining detected Spz1 protein in the nuclei of LFG6 Leydig cells. The ability of Spz1 protein to bind to the bHLH consensus-binding site, the E-box, was confirmed by EMSA, and a 9-bp asymmetric target site was identified by random selection and PCR amplification. Hormonal regulation of Spz1 was investigated and downregulation of Spz1 expression by testosterone and retinoic acid was found. This nuclear transcription factor may play a crucial role in spermatogenesis by regulating cell proliferation or differentiation through binding to specific DNA sequences like other bHLH-Zip molecules.

Original languageEnglish
Pages (from-to)177-187
Number of pages11
JournalMechanisms of Development
Issue number2
Publication statusPublished - 2001
Externally publishedYes


  • Basic helix-loop-helix
  • Leucine zipper
  • Mouse
  • Spermatogenesis
  • Testis

ASJC Scopus subject areas

  • Embryology
  • Developmental Biology


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