Polymorphic expression of DAZ proteins in the human testis.
BACKGROUND
DAZ is a male infertility gene located at the AZFc region of the Y chromosome. There are four copies of the DAZ gene that share a strong homology but are not identical to one another. In the present study, we carried out cDNA cloning and immunoblot analyses to determine whether all of the DAZ genes are actively expressed in the human testis.


METHODS
AZFc deletion was detected by sequence-tagged site polymerase chain reaction (PCR) of genomic DNA isolated from blood samples. DAZ cDNAs were cloned with RT-PCR followed by sequence analysis. The expression of DAZ proteins in human testis was determined by immunoblot and compared with DAZ cDNA expression.


RESULTS
Immunoblot analysis revealed four DAZ protein bands in testis samples that showed no deletions in the AZFc region. No specific bands were observed in samples from AZFc deletion patients. Testis samples from individuals with the partial AZFc deletion, gr/gr, showed two DAZ-specific bands. Interestingly, the sizes of DAZ-specific bands varied among individuals. Analysis of DAZ transcripts in testis samples revealed that the DAZ proteins were translated from the largest of the multiple transcripts originating from each single DAZ gene.


CONCLUSIONS
All four DAZ genes are expressed in the human testis, and their products are highly polymorphic among men.
Kim
Byunghyuk
B
Department of Biological Sciences, Seoul National University, Seoul 151-747, Korea.
Lee
Youngbin
Y
Kim
Yeonwha
Y
Lee
Kyung Ho
KH
Chun
Sunhye
S
Rhee
Kunsoo
K
Seo
Ju Tae
JT
Kim
Soo Woong
SW
Paick
Jae-Seung
JS
D000918:Antibody Specificity; D002460:Cell Line; D041322:Chromosomes, Human, Y; D003001:Cloning, Molecular; D000075364:Deleted in Azoospermia 1 Protein; D017353:Gene Deletion; D018628:Gene Dosage; D006801:Humans; D007150:Immunohistochemistry; D007248:Infertility, Male / Q000235:genetics*; D008297:Male; D011110:Polymorphism, Genetic; D016601:RNA-Binding Proteins / Q000235:genetics* / Q000276:immunology / Q000378:metabolism; D013737:Testis / Q000502:physiology*; D014162:Transfection
C095668:DAZ1 protein, human; C459440:DAZ2 protein, human; C543054:DAZ3 protein, human; C543055:DAZ4 protein, human; C101358:DAZL protein, human; D000075364:Deleted in Azoospermia 1 Protein; D016601:RNA-Binding Proteins