Identification of a New Enhancer That Promotes Sox9 Expression by a Comparative Analysis of Mouse and Sry-Deficient Amami Spiny Rat

INTRODUCTION

Testis differentiation is initiated by the SRY gene on the Y chromosome in mammalian species. However, the Amami spiny rat, Tokudaia osimensis, lacks both the Y chromosome and the Sry gene and acquired a unique Sox9 regulatory mechanism via a male-specific duplication upstream of Sox9, without Sry. In general mammalian species, the SRY protein binds to a testis-specific enhancer to promote SOX9 gene expression. Several enhancers located upstream of Sox9/SOX9 have been reported in mice and humans. In particular, the binding of SRY to the highly conserved enhancer Enh13 is thought to be a common mechanism underlying testis differentiation and sex determination in mammals.

METHODS

Sequences of T. osimensis homologues of three Sox9 enhancers that were previously reported in mice, Enh8, Enh14, and Enh13, were determined. We performed in vitro assays to confirm enhancer activity involved in Sox9 regulation in T. osimensis.

RESULTS

T. osimensis Enh13 showed enhancer activity when co-transfected with NR5A1 and SOX9. Mouse Enh13 was activated by NR5A1 and SRY; however, T. osimensis Enh13 did not respond to SRY, even though the binding sites of SRY and NR5A1 were conserved. To identify the key sequence that is present in mouse but absent from T. osimensis, we performed reporter gene assays using vectors in which partial sequences of T. osimensis Enh13 were replaced with mouse sequences. For T. osimensis Enh13 in which the second half (approximately 430 bp) was replaced with the corresponding mouse sequence, activity in response to NR5A1 and SRY was recovered. Further, reporter assays revealed that multiple regions in the second half of the mouse Enh13 sequence are required for the response to NR5A1 and SRY. The latter 49 bp was particularly important and contained four binding sites for three transcription factors, POU2F1, HOXA3, and GATA1.

CONCLUSION

We showed that there are unknown sequences responsible for the interaction between NR5A1 and SRY and mEnh13 based on comparative analyses of Sry-dependent and Sry-independent species. Our comparative analyses revealed new molecular mechanisms underlying mammalian sex determination.

Hemodynamic mechanism of erection in the human penis

Six infertile patients and one patient with ureteral calculus were studied to elucidate the intrapenial hemodynamics of erection. Xe-133 was infused into the corpus cavernosum and visual sexual stimulation (V.S.S.) provided to induce erection. Xe-133 clearance curves declined at a uniform rate in the nonerect penis without V.S.S. Xe-133 clearance curves for five patients with complete erection at V.S.S. indicated a sudden drop upon erection. Unlike previous reports, it was noted that penial erection can occur independently of a venous-return blocking mechanism.

Sperm motile efficiency

To provide an alternative to presently available subjective ways of measuring sperm motility which often yield inconsistent data, we devised a method for determining sperm motile efficiency with it one can express objectively the amount of active sperm movement. Using a melangeur for counting white cell, semen is diluted 20-fold in normal saline solution. With the diluted semen on Thoma's hemocytometer, spermatozoa passing its small quarter line in one minute are counted, and the value is divided by the estimated number of spermatozoa per ml. The quotient is multiplied by 100 and expressed by %/min. This shows the active movement of a spermatozoon per minute. In the present study, we measured sperm motile efficiency in 162 male sterility patients, 64 cases showed values of 49%/min or less, with a mean of 20.3%/min, 46, between 50%/min and 99%/min, with a mean of 70.1%/min; and the remaining 52 over 100%/min, with a mean of 195.9%/min. Among these there were 10 cases of successful pregnancy with a mean sperm motile efficiency of 152.7%/min, and 69.0%/min at the lowest. Our new method requiring no special equipment can easily identify active sperm movement and is easily reproducible,

Determination of intrapenial blood volume using 99mTc-labeled autologous red blood cells

In 17 impotent patients, radioisotope penography was performed using 99mTc-red blood cells (the patient's own red blood cells labeled with 99mTc) for the quantitative analysis of intrapenial blood volume. A visual sexual stimulation (VSS) was given to the patient after injecting the 99mTc-red blood cells. Patients showing a complete erection had their intrapenial blood volumes 4.2-11.2 times greater than before VSS (mean increase, 8.0 times). In cases of incomplete erection after VSS the intrapenial blood volumes were 3.3-7.0 times greater than before VSS (mean increase, 4.9 times). In cases showing a gentle rise in their penogram curves without evidence of an erection, intrapenial blood volumes after VSS were 2.0-3.3 times those before VSS (mean increaae, 2.9 times). By contrast, in cases showing no response to the VSS or no rise in penogram curve, post-VSS increases in intrapenial pool of blood were very slight, slight, only 1.4-1.7 times the original volume of blood.

Visualization of the human cavernosum penis by using 99mTc-labeled autologous red blood cells

Penial scintiphoto-images were obtained by using 99mTc-labeled autologous red blood cells in three functionally impotent patients. The cavernosum penis was clearly pictured disclosing no organic abnormalities in these three patients' penises. This method enables one to present clear macroscopic images of the cavernosum penis without causing pain to the patient, and it may be recommended for clinical use as an alternative to cavernosography.

A case of Wegener's granulomatosis with necrosis of the penis

A 31-year-old male had a sudden onset of painful swelling in the penile root region. He then developed necrosis of the penis and further a progressive, chemotherapy-resistant ulcer which involved the perineal region also. Histologically there was evidence of neither malignancy nor specific inflammation, but there were granulomatous tissues with cellular infiltration and scattered vascular necrosis. Examination of the nose suggested gangrenous rhinitis with perforation of the nasal septum. X-ray examination revealed that the nasal septum and conchae had disappeared. Chest roentgenogram also revealed increased hilar shadows in both fields of the chest. Routine laboratory examinations showed slight albuminuria and a normal BUN level. Positive findings included leucocytosis, hyper-gamma-globulinemia, accelerated ESR, positive RA and CRP tests. The patient's death was caused by bleeding from gastric ulcer and pulmonary failure.

Changes in plasma levels of LH, FSH and testosterone following the administration of synthetic luteinizing hormone-releasing hormone to cryptorchid patients

The levels of LH, FSH and testosterone of three adult groups consisting of normal subjects, unilateral and bilateral cryptorcids were compared before and after LH-RH loading. It was found that both groups of cryptorchid had comparatively high plasma base line levels for both LH and FSH, particularly high in the bilateral group; and both groups responded to LH-RH loading. This indicates that their hypothalamo-hypophyseal systems were probably functioning normally. The plasma base line levels of testosterone were higher in unilateral cryptorchids than in the control group, and lowest in the bilateral cryptorchid group. But the reaction of testosterone levels to LH-RH loading was generally poor in both groups of cryptorchids, suggesting that, in cryptorchid cases, unilateral and bilateral, the capacity of the testicle to secrete testosterone is generally depressed, freeing central suppression. This probably accounts for the high values of plasma lh and FSH observed in such patients.

FSH, LH and testosterone levels in human seminal plasma

Testosterone levels in the seminal plasma of 5 normal males, and 30 male sterility patients were measured by radioimmunoassay. In 9 random cases, seminal plasma levels of FSH and LH were determined by radioimmunoassay. The average level of seminal plasma testosterone for the normal males was 72 +/- ng/100 ml, higher than that of the patients: 52 +/- 41 ng/100 ml. The average levels of FSH and LH in the seminal plasma of the 9 random cases were 4.4 +/- 2.0 mIU/ml and 35.4 +/- 5.4 mlU/ml, respectively.

Impetus to transferring non-motile sperm in the seminiferous tubules into the epididymis

Effect of intratesticular pressure was examined on non-motile sperms in the testis whether they move toward the epididymis when it is raised. The head portion of the epididymis of the dog was cut apart at the proximal portion to the testis fully exposing the lumen of the epididymis. The electric stimulation of perivascular nerves of the spermatic cord caused spermatozoa to flow out onto the incision site at 5 min. The number of them increased progressively, almost innumerable at 15 min. These results support the view that the elevated intratesticular pressure by electric stimulation surely works to transfer non-motile sperm in the seminiferous tubules into the epididymis.