Evolutionary conservation of the gene C vs ox9 in the lizard, Calotes versicolor , and its expression during gonadal differentiation

Choudhary, Bibha; Ganesh, Subramaniam; Raman, Rajiva

doi:10.1007/s004270050311

Cited by 13 publications

(12 citation statements)

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“…At the time of hatching (i.e., at stage 42) the Mullerian ducts were absent in males, whereas in females the oviducts were distinct (unpublished data). Further, for the same species Choudhary et al (2000) have suggested that the gonad remains bipotential throughout embryogenesis, and it is not until about 15 days of hatching that the individual has only a testis or only an ovary; also, both Mullerian and Wolffian ducts regress only after 15 days of hatching. Generally, regression of Mullerian duct begins soon after testicular differentiation (Fox,'77;Raynaud and Pieau,'85;Austin,'89;Wibbels et al,'99).…”

Section: Discussionmentioning

confidence: 95%

“…On the other hand, three distinct patterns of gonadal differentiation (testis, ovary, and indifferent stages) were observed in histological sections of 8-10-day-old hatchlings of C. versicolor (Ganesh and Raman,'95). Recently, Choudhary et al (2000) have opined that differentiation of gonads in C. versocolor is not completed until about 15 days after hatching because of the substantial presence of the cortex and medulla. In a detailed investigation of the developing gonad of the same species, I observed that the gonadal component was in the form of a genital ridge at embryonic stage 27 (oviposition), and the sex differentiation of the gonads occurred at embryonic stage 34 (Doddamani,'94).…”

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confidence: 98%

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Differentiation and development of testis in the oviparous lizard,Calotes versicolor (Daud.)

Doddamani

2006

J. Exp. Zool.

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The differentiation and development of the testis in the lizard Calotes versicolor was studied histologically and histoenzymatically from the day of oviposition (stage 27) to 2 months after hatching. The study reveals the appearance of the gonadal component as a genital ridge at stage 27. The first sign of testis differentiation is observed at stage 33, which displays a well-developed medulla consisting of seminiferous cords comprising Pre-Sertoli cells. The sex differentiation of the embryonic gonads occurs at stage 34. At this stage, seminiferous cords of the testis are prominent and extensive with many pre-Sertoli cells and few spermatogonia. The interstitial space consists of immature fibroblast-type Leydig cells. Pre-Sertoli cells of the seminiferous cords differentiate into Sertoli cells with a triangular nucleus becoming apparent around stages 36-37. The fibroblast-like Leydig cells differentiate into round matured Leydig cells at stage 40. Quantitative estimation of germ cells reveals that the number of germ cells increases in individual gonads, and in 5-day-old hatchling's, this number multiplies by manifold. Spermatogonia show reductional division in the testis of 1-day-old hatchlings. Histochemical localization of Delta5-3beta-HSDH and G-6-PDH activity appears in the seminiferous cords (medulla) of the testis after sexual differentiation (stage 36), indicating that the embryonic medulla is the site of steroidogenesis and not the cortex in C. versicolor. This study also suggests that morphological differentiation of the gonad precedes detectable steroidogenesis in this species. In 10-day-old hatchling's, Delta5-3beta-HSDH activity is seen in the interstitial cells of the testis, which, however, is not detected in the seminiferous tubules. The intensity of the enzyme activity remains more or less the same in the testis up to 10 days after hatching and begins to increase thereafter. The increase in steroidogenesis parallels the progressive post-hatching increase of the interstitial/Leydig cells.

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Section: Discussionmentioning

confidence: 95%

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confidence: 98%

Differentiation and development of testis in the oviparous lizard,Calotes versicolor (Daud.)

Doddamani

2006

J. Exp. Zool.

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“…To date, the sox9 gene has been identified in several vertebrate species including mammals (Foster et al 1994, Wagner et al 1994, Kent et al 1996, birds (Morais da Silva et al 1996), reptiles (Moreno-Mendoza et al 1999, Western et al 1999, Choudhary et al 2000, amphibians (Takase et al 2000), and fishes (Takamatsu et al 1997, Chiang et al 2001, Yokoi et al 2002. Two different forms of sox9 genes have been identified in teleosts like zebrafish, rice field eel, fugu, and medaka (Chiang et al 2001, Zhou et al 2003, Koopman et al 2004, Klü ver et al 2005.…”

Section: Introductionmentioning

confidence: 99%

Isolation of sox9 duplicates in catfish: localization, differential expression pattern during gonadal development and recrudescence, and hCG-induced up-regulation of sox9 in testicular slices

Kavarthapu¹,

Senthilkumaran²

2010

Reproduction

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In vertebrates, sox9 is a transcription factor that plays a crucial role in testicular development and chondrogenesis. Here, we report cloning of isoforms of sox9 (sox9a and sox9b) from air-breathing catfish Clarias gariepinus, which undergoes an annual reproductive cycle. Tissue distribution pattern showed differential expression of sox9 duplicates, wherein both forms were highly expressed in brain and gonads. Furthermore, we observed a dimorphic expression pattern of sox9a and sox9b in both adult and developing gonads using RT-PCR, indicating that sox9a retained its function in testis while sox9b might have a new role to play in ovary. Changes in sox9 mRNA levels using real-time quantitative PCR (qRT-PCR) during the seasonal reproductive cycle revealed that sox9a transcript in testis was abundant during testicular recrudescence (during spermatogenesis), and its expression significantly decreased during spawning and post-spawning phases. Furthermore, treatments of human chorionic gonadotropin and 11-ketotestosterone in vitro up-regulated sox9a mRNA levels in the testicular slices at 12 and 24 h time points, suggesting that gonadotropins might stimulate sox9 expression. These results suggest that sox9 might have a plausible role in the entrainment of the testicular cycle. In contrast, during the ovarian cycle, sox9b mRNA levels gradually declined from preparatory to post-spawning phases. Immunohistochemical (IHC) data showed that, in testis, sox9 is detectable in Sertoli and spermatogonial cell types except spermatid/spermatozoa. In the ovary, it is localized in the ooplasm of primary and pre-vitellogenic oocytes. These results were further confirmed by whole-mount IHC and qRT-PCR.

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“…(44,45) In most eutherian mammals, sex is determined by the presence of the SRY gene on the Y chromosome. (46) SRY is present on the Y chromosome of marsupials (47) but does not control all facets of sex determination in this group.…”

Section: Introductionmentioning

confidence: 99%

The ends of a continuum: genetic and temperature‐dependent sex determination in reptiles

Sarre¹,

Georges²,

Quinn³

2004

BioEssays

278

259

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Two prevailing paradigms explain the diversity of sex‐determining modes in reptiles. Many researchers, particularly those who study reptiles, consider genetic and environmental sex‐determining mechanisms to be fundamentally different, and that one can be demonstrated experimentally to the exclusion of the other. Other researchers, principally those who take a broader taxonomic perspective, argue that no clear boundaries exist between them. Indeed, we argue that genetic and environmental sex determination in reptiles should be seen as a continuum of states represented by species whose sex is determined primarily by genotype, species where genetic and environmental mechanisms coexist and interact in lesser or greater measure to bring about sex phenotypes, and species where sex is determined primarily by environment. To do otherwise limits the scope of investigations into the transition between the two and reduces opportunities to use studies of reptiles to advance understanding of vertebrate sex determination generally. BioEssays 26:639–645, 2004. © 2004 Wiley Periodicals, Inc.

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Evolutionary conservation of the gene C vs ox9 in the lizard, Calotes versicolor , and its expression during gonadal differentiation

Cited by 13 publications

References 28 publications

Differentiation and development of testis in the oviparous lizard,Calotes versicolor (Daud.)

Differentiation and development of testis in the oviparous lizard,Calotes versicolor (Daud.)

Isolation of sox9 duplicates in catfish: localization, differential expression pattern during gonadal development and recrudescence, and hCG-induced up-regulation of sox9 in testicular slices

The ends of a continuum: genetic and temperature‐dependent sex determination in reptiles

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