scholarly journals Genetic Dissection of the AZF Regions of the Human Y Chromosome: Thriller or Filler for Male (In)fertility?

2010 ◽  
Vol 2010 ◽  
pp. 1-18 ◽  
Author(s):  
Paulo Navarro-Costa ◽  
Carlos E. Plancha ◽  
João Gonçalves
Keyword(s):  
Y Chromosome ◽  
Male Fertility ◽  
Molecular Mechanisms ◽  
Gene Families ◽  
Comprehensive Analysis ◽  
Gene Content ◽  
Genetic Dissection ◽  
Azoospermia Factor ◽  
Or Gene ◽  
Human Y Chromosome

The azoospermia factor (AZF) regions consist of three genetic domains in the long arm of the human Y chromosome referred to as AZFa, AZFb and AZFc. These are of importance for male fertility since they are home to genes required for spermatogenesis. In this paper a comprehensive analysis of AZF structure and gene content will be undertaken. Particular care will be given to the molecular mechanisms underlying the spermatogenic impairment phenotypes associated to AZF deletions. Analysis of the 14 different AZF genes or gene families argues for the existence of functional asymmetries between the determinants; while some are prominent players in spermatogenesis, others seem to modulate more subtly the program. In this regard, evidence supporting the notion thatDDX3Y,KDM5D,RBMY1A1,DAZ, andCDYrepresent key AZF spermatogenic determinants will be discussed.

scholarly journals The role of Y chromosome deletions in male infertility

2000 ◽  
pp. 418-430 ◽  
Author(s):  
K Ma ◽  
C Mallidis ◽  
S Bhasin
Keyword(s):  
Male Infertility ◽  
Y Chromosome ◽  
Genetic Research ◽  
Gene Families ◽  
Azoospermia Factor ◽  
The World ◽  
Number Of Genes ◽  
Chromosome Deletions ◽  
Or Gene

Male infertility affects approximately 2-7% of couples around the world. Over one in ten men who seek help at infertility clinics are diagnosed as severely oligospermic or azoospermic. Recent extensive molecular studies have revealed that deletions in the azoospermia factor region of the long arm of the Y chromosome are associated with severe spermatogenic impairment (absent or severely reduced germ cell development). Genetic research into male infertility, in the last 7 years, has resulted in the isolation of a great number of genes or gene families on the Y chromosome, some of which are believed to influence spermatogenesis.

scholarly journals Analysis of DAZ gene expression in a partial AZFc deletion of the human Y chromosome

2014 ◽  
Vol 26 (2) ◽  
pp. 307 ◽  
Author(s):  
Byunghyuk Kim ◽  
Wonkyung Lee ◽  
Kunsoo Rhee ◽  
Soo Woong Kim ◽  
Jae-Seung Paick
Keyword(s):  
Y Chromosome ◽  
Pcr Assay ◽  
Azfc Region ◽  
Azoospermia Factor ◽  
Azfc Deletion ◽  
Deleted In Azoospermia ◽  
Polymerase Chain ◽  
Factor C ◽  
Human Y Chromosome ◽  
Daz Gene

The azoospermia factor c (AZFc) region of the Y chromosome consists of repetitive amplicons and is therefore highly susceptible to structural rearrangements, such as deletions and duplications. The b2/b3 deletion is a partial AZFc deletion that is conventionally determined by the selective absence of sY1191 in sequence-tagged site polymerase chain reaction (PCR) and is generally believed to retain two of the four deleted in azoospermia (DAZ) genes on the Y chromosome. In the present study we determined the copy number and expression of DAZ genes in sY1191-negative individuals. Using a DAZ dosage PCR assay and Southern blot analysis we evaluated the expression of four DAZ genes in five of six sY1191-negative individuals. Furthermore, cloning and immunoblot analyses revealed that three or more DAZ genes are expressed in sY1191-negative testes with germ cells. The results indicate that the selective absence of sY1191 not only means b2/b3 deletion with two DAZ genes, but also includes another AZFc configuration with four DAZ genes. These results exemplify the prevalence of variations in the AZFc region of the human Y chromosome.

The azoospermia factor (AZF) of the human Y chromosome in Yq11: function and analysis in spermatogenesis

1995 ◽  
Vol 7 (4) ◽  
pp. 685 ◽  
Author(s):  
PH Vogt ◽  
A Edelmann ◽  
P Hirschmann ◽  
MR Kohler
Keyword(s):  
Y Chromosome ◽  
Chromatin Structure ◽  
De Novo ◽  
Screening Programme ◽  
Deletion Mapping ◽  
Azoospermia Factor ◽  
Its Analysis ◽  
Human Y Chromosome

Different Y mutations in Yq11 occurring de novo in sterile males were first described 19 years ago. Since the phenotype of the patients was always associated with azoospermia or severe oligospermia, it was postulated that these mutations interrupt a Y spermatogenesis locus in the euchromatic Y region (Yq11) called azoospermia factor (AZF). Recently, it became possible to map AZF mutations to different subregions in Yq11 by molecular deletion mapping. This indicated that azoospermia is possibly caused by more than one Y gene in Yq11 and the Yq11 chromatin structure. The frequency of AZF mutations in idiopathic sterile males (5-20%) may indicate a need for a general screening programme for its analysis in infertility clinics.

scholarly journals Birth, expansion, and death of VCY-containing palindromes on the human Y chromosome

2019 ◽  
Vol 20 (1) ◽  
Author(s):  
Wentao Shi ◽  
Andrea Massaia ◽  
Sandra Louzada ◽  
Juliet Handsaker ◽  
William Chow ◽  
...  
Keyword(s):  
Y Chromosome ◽  
Sex Chromosomes ◽  
Structural Variation ◽  
Molecular Mechanisms ◽  
Mammalian Species ◽  
Inverted Repeats ◽  
Palindromic Structure ◽  
Genomic Disorders ◽  
Adjacent Sequence ◽  
Human Y Chromosome

Abstract Background Large palindromes (inverted repeats) make up substantial proportions of mammalian sex chromosomes, often contain genes, and have high rates of structural variation arising via ectopic recombination. As a result, they underlie many genomic disorders. Maintenance of the palindromic structure by gene conversion between the arms has been documented, but over longer time periods, palindromes are remarkably labile. Mechanisms of origin and loss of palindromes have, however, received little attention. Results Here, we use fiber-FISH, 10x Genomics Linked-Read sequencing, and breakpoint PCR sequencing to characterize the structural variation of the P8 palindrome on the human Y chromosome, which contains two copies of the VCY (Variable Charge Y) gene. We find a deletion of almost an entire arm of the palindrome, leading to death of the palindrome, a size increase by recruitment of adjacent sequence, and other complex changes including the formation of an entire new palindrome nearby. Together, these changes are found in ~ 1% of men, and we can assign likely molecular mechanisms to these mutational events. As a result, healthy men can have 1–4 copies of VCY. Conclusions Gross changes, especially duplications, in palindrome structure can be relatively frequent and facilitate the evolution of sex chromosomes in humans, and potentially also in other mammalian species.

Azoospermia Factor a (AZFa) sub-region of human Y-chromosome: A review

Meta Gene ◽  
2017 ◽  
Vol 13 ◽  
pp. 124-128 ◽  
Author(s):  
Mili Nailwal ◽  
Jenabhai B. Chauhan
Keyword(s):  
Y Chromosome ◽  
Azoospermia Factor ◽  
Human Y Chromosome

scholarly journals Deletion of azoospermia factor a (AZFa) region of human Y chromosome caused by recombination between HERV15 proviruses

2000 ◽  
Vol 9 (15) ◽  
pp. 2291-2296 ◽  
Author(s):  
C. Sun ◽  
H. Skaletsky ◽  
S. Rozen ◽  
J. Gromoll ◽  
E. Nieschlag ◽  
...  
Keyword(s):  
Y Chromosome ◽  
Azoospermia Factor ◽  
Human Y Chromosome

scholarly journals The Human Y Chromosome: The Biological Role of a “Functional Wasteland”

2001 ◽  
Vol 1 (1) ◽  
pp. 18-24 ◽  
Author(s):  
Lluís Quintana-Murci ◽  
Marc Fellous
Keyword(s):  
Y Chromosome ◽  
Male Fertility ◽  
Its Sequence ◽  
Distinguishing Characteristic ◽  
Biological Functions ◽  
Sry Gene ◽  
Male Phenotype ◽  
Mammalian Embryos ◽  
Human Y Chromosome

“Functional wasteland,” “Nonrecombining desert” and “Gene-poor chromosome” are only some examples of the different definitions given to the Y chromosome in the last decade. In comparison to the other chromosomes, the Y is poor in genes, being more than 50% of its sequence composed of repeated elements. Moreover, the Y genes are in continuous decay probably due to the lack of recombination of this chromosome. But the human Y chromosome, at the same time, plays a central role in human biology. The presence or absence of this chromosome determines gonadal sex. Thus, mammalian embryos with a Y chromosome develop testes, while those without it develop ovaries (Polani [38]). What is responsible for the male phenotype is the testis-determining SRY gene (Sinclair [52]) which remains the most distinguishing characteristic of this chromosome. In addition to SRY, the presence of other genes with important functions has been reported, including a region associated to Turner estigmata, a gene related to the development of gonadoblastoma and, most important, genes related to germ cell development and maintenance and then, related with male fertility (Lahn and Page [31]). This paper reviews the structure and the biological functions of this peculiar chromosome.

Mammalian Sex Chromosome Structure, Gene Content, and Function in Male Fertility

2019 ◽  
Vol 7 (1) ◽  
pp. 103-124 ◽  
Author(s):  
Wan-Sheng Liu
Keyword(s):  
Sex Chromosomes ◽  
Sexual Development ◽  
Brain Function ◽  
Male Fertility ◽  
Sex Chromosome ◽  
Size Structure ◽  
Gene Families ◽  
Gene Content ◽  
Meiotic Sex Chromosome Inactivation ◽  
And Function

Mammalian sex chromosomes evolved from an ordinary pair of autosomes. The X chromosome is highly conserved, whereas the Y chromosome varies among species in size, structure, and gene content. Unlike autosomes that contain randomly mixed collections of genes, the sex chromosomes are enriched in testis-biased genes related to sexual development and reproduction, particularly in spermatogenesis and male fertility. This review focuses on how sex chromosome dosage compensation takes place and why meiotic sex chromosome inactivation occurs during spermatogenesis. Furthermore, the review also emphasizes how testis-biased genes are enriched on the sex chromosomes and their functions in male fertility. It is concluded that sex chromosomes are critical to sexual development and male fertility; however, our understanding of how sex chromosome genes direct sexual development and fertility has been hampered by the structural complexities of the sex chromosomes and by the multicopy nature of the testis gene families that also play a role in immunity, cancer development, and brain function.

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