Expression of Apg-1, a member of the Hsp110 family, in the human testis and sperm

BACKGROUND

Apg-1 encodes a heat shock protein belonging to the Hsp110 family and is inducible by a 32 degrees C to 39 degrees C heat shock in somatic cells. In mouse testicular germ cells Apg-1 mRNA is constitutively expressed depending on the developmental stage. As human Apg-1 has recently been identified, the expression of Apg-1 in the human testis and sperm was investigated.

METHODS

Expression and heat-inducibility of Apg-1 in the human testicular germ cell tumor cell line, NEC8, was analyzed. Using an antimouse Apg-1 antibody, expression of Apg-1 in the human testis and sperm was examined by western blotting after confirmation of the specificity of the antibody. The cells expressing Apg-1 in the testis were further determined by immunohistochemistry.

RESULTS

Slight induction of Apg-1 mRNA was detected in NEC8 cells after 32 degrees C to 39 degrees C temperature shift. In the human testis, the antibody specifically recognized Apg-1, which was absent in the testis without germ cells (Sertoli-cell-only syndrome) or arrested at spermatogonia. Spermatocytes and spermatids, but not testicular somatic cells, were positively stained with the anti-Apg-1 antibody. By western blot analysis, Apg-1 was detected in the preparation enriched for sperm from normal volunteers and infertile patients, but not from azoospermia patients.

CONCLUSION

Apg-1 is developmentally expressed in human testicular germ cells and sperm, suggesting its role in spermatogenesis and fertilization. Identification of substrates for Apg-1 chaperone activity will help elucidate its function.

Expression of protein tyrosine phosphatase PTP-RL10 and its isoform in the mouse testis

BACKGROUND

The cytoplasmic-type protein tyrosine phosphatase PTP-RL10/PTPD1/PTP2E contains an ezrin-like domain and associates with the c-Src protein tyrosine kinase. Because tyrosine phosphorylation regulated by protein tyrosine kinases and phosphatases is involved in activation, migration, differentiation and proliferation of various cell types, the expression of PTP-RL10 and c-src in the mouse testis was investigated.

METHODS

Testes of wild-type mice and W/W(v) mutant mice that lack germ cells were analyzed by northern blotting, in situ hybridization histochemistry and reverse transcriptase-polymerase chain reaction for the expression of PTP-RL10, its isoform PTP-RL10b and c-src. Expression in the Sertoli cell lines, TM4 and TAMA26 was also analyzed.

RESULTS

PTP-RL10 transcripts of 5.7kb and 2.9kb in size were detected in the testis. In situ hybridization histochemistry demonstrated that the 5.7kb transcripts were expressed in pachytene spermatocytes and somatic cells including Sertoli cells, in which c-src transcripts were detected. The 2.9kb transcript encoded a novel isoform, PTP-RL10b, that has the catalytic domain but not the domains that associate with c-Src. PTP-RL10b was expressed mainly in the testicular somatic cells. TM4 and TAMA26 cells were found to co-express PTP-RL10, PTP-RL10b and c-src transcripts.

CONCLUSION

PTP-RL10 and its isoform are expressed in the Sertoli cells and are suggested to play roles in spermatogenesis by interacting with c-Src and/or other protein(s).

Cloning of human cDNAs for Apg-1 and Apg-2, members of the Hsp110 family, and chromosomal assignment of their genes

In mice, the Hsp110/SSE family is composed of the heat shock protein (Hsp)110/105, Apg-1 and Apg-2. In humans, however, only the Hsp110/105 homolog has been identified as a member, and two cDNAs, Hsp70RY and HS24/p52, potentially encoding proteins structurally similar to, but smaller than, mouse Apg-2 have been reported. To clarify the membership of Hsp110 family in humans, we isolated Apg-1 and Apg-2 cDNAs from a human testis cDNA library. The human Apg-1 was 100% and 91.8% identical in length and amino acid (aa) sequence, respectively, to mouse Apg-1. Human Apg-2 was one aa shorter than and 95.5% identical in sequence to mouse Apg-2. In ECV304, human endothelial cells Apg-1 but not Apg-2 transcripts were induced in 2 h by a temperature shift from 32 degrees C to 39 degrees C. As found in mice, the response was stronger than that to a 37-42 degrees C shift. The human Apg-1 and Apg-2 genes were mapped to the chromosomal loci 4q28 and 5q23.3-q31.1, respectively, by fluorescence in-situ hybridization. We isolated cDNA and genomic clones encompassing the region critical for the difference between Apg-2 and HS24/p52. Although the primer sets used were derived from the sequences common to both cDNAs, all cDNA and genomic clones corresponded to Apg-2. Using a similar approach, the relationship between Apg-2 and Hsp70RY was assessed, and no clone corresponding to Hsp70RY was obtained. These results demonstrated that the Hsp110 family consists of at least three members, Apg-1, Apg-2 and Hsp110 in humans as well as in mice. The significance of HS24/p52 and Hsp70RY cDNAs previously reported remains to be determined.

[A case of genital Paget's disease with severe dermal invasion and early dissemination]

A 65-year-old man was referred to our hospital with a complaint of a scrotal mass which he first noticed 8 months ago. The mass was resected saving genital organs. Pathological diagnosis was extramammary Paget's disease with severe dermal invasion and many nuclear mitoses. The tumor was 15 mm in diameter, and 18 mm in thickness. The bilateral inguinal lymph nodes were dissected and multiple metastases were revealed in the right specimen. Since paraaortic lymph node metastases were detected later 5 cycles of chemotherapy consisting of cyclophosphamide, adriamycin and cisplatin (CAP) followed by radiation therapy were performed. However, only a partial response could be obtained, and multiple brain metastases were revealed on computed tomographic scan. He died 22 months after discovery of this disease. Since extramammary Paget's disease tends to grow slowly and horizontally, cases with such severe dermal invasion and early dissemination as in our case are unusual.

[Urinary erythrocyte morphology under optical microscopy: value in the urological outpatient clinic]

Urinary erythrocyte morphology was examined by optical microscopy 1,256 urological patients with hematuria, between 1990 and 1993. The patients were grouped according to whether their urinary red cells were glomerular origin or non-glomerular in origin or mixed form, or others. Of the 740 patients in the glomerular group 537 were examined urologically, and some urological disease was found in 78 (15%) patients. Urological disease was found in only 7 (2%) of the 316 patients in the glomerular group whose complaint was only asymptomatic microscopic hematuria. Examination of urinary erythrocyte morphology under optical microscopy is inexpensive and valuable in the urological outpatient clinic.