Two testicular cDNA clones suppressed by gonadotropin stimulation exhibit ZP2‐ and ZP3‐like structures in Japanese eel

Abstract

A single injection of human chorionic gonadotropin (HCG) can induce complete spermatogenesis in immature eel testes consisting of premitotic spermatogonia. To understand the regulatory mechanisms of spermatogenesis, we have applied a subtractive hybridization method to identify genes in which changes in expression occur after HCG treatment in vivo. The subtraction was carried out 24 hours after HCG injection. Two up-regulated and six down-regulated cDNA clones by HCG stimulation were isolated, and named eel spermatogenesis-related substance (eSRS) 1 to 8. In this paper, down-regulated cDNA clones of eSRS3 and eSRS4 were sequenced. A homology search showed that eSRS3 and eSRS4 have amino acid sequences similar to those of the ZP-domains of zona pellucida sperm-binding protein (ZP)-2 and 3, respectively. Transcripts of eSRS3 and eSRS4 have been detected only in immature testes and ovaries. Both transcripts disappeared immediately after HCG injection and were not detected in testes throughout the experimental period. To determine whether HCG action on down-regulation of eSRS3 and eSRS4 transcription is direct or mediated through 11-ketotestosterone (11-KT), a spermatogenesis-inducing steroid in eel, we investigated the effect of HCG and 11-KT on testicular eSRS3 and eSRS4 mRNA transcription in vitro. Northern blot analysis using poly(A)+ RNA extracted from cultured testis showed that both HCG and 11-KT suppressed the mRNA transcription of both eSRS3 and eSRS4. We speculate that eSRS3 and eSRS4 may play important roles in the prevention of spermatogenesis in the eel.

Dynamic Gene Expression and Alternative Splicing Events Demonstrate Co-Regulation of Testicular Differentiation and Maturation by the Brain and Gonad in Common Carp

“…Previous studies have reported that zp3l is a malebiased gene, located in the zona pellucida, and is essential in sperm binding and zona matrix formation (52)(53)(54). Moreover, zp3l has been identified as a reproduction-related gene (55), which exhibits inhibition by gonadotropin stimulation (56). These results broaden existing understanding of signaling in the brain and testes that regulates gonad development, thereby providing a new research perspective for reproductive regulation research.…”

Dynamic Gene Expression and Alternative Splicing Events Demonstrate Co-Regulation of Testicular Differentiation and Maturation by the Brain and Gonad in Common Carp

“…Previous studies have reported that zp3l is a malebiased gene, located in the zona pellucida, and is essential in sperm binding and zona matrix formation (52)(53)(54). Moreover, zp3l has been identified as a reproduction-related gene (55), which exhibits inhibition by gonadotropin stimulation (56). These results broaden existing understanding of signaling in the brain and testes that regulates gonad development, thereby providing a new research perspective for reproductive regulation research.…”

Analysis of Spermatogenesis Using an Eel Model

“…To further elucidate the key genes involved in spermatogonial proliferation toward meiosis, we performed screening of stage-specific genes during eel spermatogenesis using cDNA subtraction and differential display methods (Miura et al 1998;. The key genes coding factors that showed unique expression during spermatogenesis were considered.…”

Fish ‘n’ chips: the use of microarrays for aquatic toxicology

“…While this is still a far cry from having a whole transcriptome, a number of labs have successfully used this approach. [30][31][32][33][34][35][36][37][38][39][40][41][42][43] For example, Sheader et al 38 used a custom cDNA microarray to identify up-regulation of 27 transcripts, including Cu/Zn superoxide dismutase, thioredoxin, a peroxiredoxin and a glutathione-S-transferase, in European flounder (Platichthys flesus) exposed to cadmium. The experiment highlighted a number of candidate genes for further analysis as potential biomarkers for cadmium exposure.…”

Dynamic Gene Expression and Alternative Splicing Events Demonstrate Co-Regulation of Testicular Differentiation and Maturation by the Brain and Gonad in Common Carp

“…Previous studies have reported that zp3l is a malebiased gene, located in the zona pellucida, and is essential in sperm binding and zona matrix formation (52)(53)(54). Moreover, zp3l has been identified as a reproduction-related gene (55), which exhibits inhibition by gonadotropin stimulation (56). These results broaden existing understanding of signaling in the brain and testes that regulates gonad development, thereby providing a new research perspective for reproductive regulation research.…”

Analysis of Spermatogenesis Using an Eel Model

“…To further elucidate the key genes involved in spermatogonial proliferation toward meiosis, we performed screening of stage-specific genes during eel spermatogenesis using cDNA subtraction and differential display methods (Miura et al 1998;. The key genes coding factors that showed unique expression during spermatogenesis were considered.…”

Fish ‘n’ chips: the use of microarrays for aquatic toxicology

“…While this is still a far cry from having a whole transcriptome, a number of labs have successfully used this approach. [30][31][32][33][34][35][36][37][38][39][40][41][42][43] For example, Sheader et al 38 used a custom cDNA microarray to identify up-regulation of 27 transcripts, including Cu/Zn superoxide dismutase, thioredoxin, a peroxiredoxin and a glutathione-S-transferase, in European flounder (Platichthys flesus) exposed to cadmium. The experiment highlighted a number of candidate genes for further analysis as potential biomarkers for cadmium exposure.…”

Dynamic Gene Expression and Alternative Splicing Events Demonstrate Co-Regulation of Testicular Differentiation and Maturation by the Brain and Gonad in Common Carp

“…Previous studies have reported that zp3l is a malebiased gene, located in the zona pellucida, and is essential in sperm binding and zona matrix formation (52)(53)(54). Moreover, zp3l has been identified as a reproduction-related gene (55), which exhibits inhibition by gonadotropin stimulation (56). These results broaden existing understanding of signaling in the brain and testes that regulates gonad development, thereby providing a new research perspective for reproductive regulation research.…”

Analysis of Spermatogenesis Using an Eel Model

“…To further elucidate the key genes involved in spermatogonial proliferation toward meiosis, we performed screening of stage-specific genes during eel spermatogenesis using cDNA subtraction and differential display methods (Miura et al 1998;. The key genes coding factors that showed unique expression during spermatogenesis were considered.…”

Fish ‘n’ chips: the use of microarrays for aquatic toxicology

“…While this is still a far cry from having a whole transcriptome, a number of labs have successfully used this approach. [30][31][32][33][34][35][36][37][38][39][40][41][42][43] For example, Sheader et al 38 used a custom cDNA microarray to identify up-regulation of 27 transcripts, including Cu/Zn superoxide dismutase, thioredoxin, a peroxiredoxin and a glutathione-S-transferase, in European flounder (Platichthys flesus) exposed to cadmium. The experiment highlighted a number of candidate genes for further analysis as potential biomarkers for cadmium exposure.…”