Characterization of HSFY, a novel AZFb gene on the Y chromosome with a possible role in human spermatogenesis

Abstract

HSFY (heat shock transcription factor, Y chromosome) has been mapped in the AZFb region of the Y chromosome, whose deletion results in severe male infertility. HSFY belongs to the heat shock factor family that has been shown to be implicated in spermatogenesis both in animals and humans. We report the characterization of the genomic structure, the number of copies on the Y chromosome and the expression of the gene. By comparison of data obtained from expression analysis and from GenBank cDNA sequences, seven exons were identified. Alternative splicing generates three different transcripts and proteins, each containing an HSF domain typical of HSF proteins. Two identical and functional full-length copies of HSFY map in palindrome P4 of AZFb, whereas four similar sequences mapping in two clusters in palindrome P1 of AZFc and P3 seem to represent pseudogenes. Sequences similar to few HSFY exons are also located in the short arm of chromosomes Y, X and 22. Expression analysis revealed that the three HSFY transcripts are differentially expressed, transcript 1 being present in many tissues including testis and ejaculated sperm, and transcripts 2 and 3 being testis-specific. These data suggest that HSFY could have an important role in human spermatogenesis.

The origin and evolution of human ampliconic gene families and ampliconic structure

“…This is consistent with the location of HSFX in stratum 1 and the k XY value of 0.992 ‫ע‬ 0.294 between HSFX and HSFY. Tessari et al (2004) proposed that HSFY arose via retroposition of HSFYL, whereas we demonstrate that the reverse happened. That is, intronless HSFYL arose via retroposition of HSFY with two exons.…”

“…Later, by examining CDYL and its early autosomal duplicate CDYL2, Dorus et al (2003) pushed the origin of CDY back before the Eutherian radiation. Regarding other gene families, it was hypothesized that retroposition resulted in HSFY (Tessari et al 2004) and transposition resulted in DAZ (Saxena et al 1996;Lahn and Page 1999a), RBMY (Chai et al 1998;Elliott et al 2000), and TSPY (Lahn and Page 1999a). However, another group proposed the proto-X/Y pair origin of RBMY (Delbridge et al 1998(Delbridge et al , 1999Lingenfelter et al 2001) and TSPY (Delbridge et al 2004).…”

Deletion or underexpression of the Y-chromosome genes CDY2 and HSFY is associated with maturation arrest in American men with nonobstructive azoospermia

“…26 These genes encode three different mRNA transcripts that are expressed in human testis. The protein translated from mRNA transcript variant 1 contains a heat-shock factor-like DNA-binding domain, 27 suggesting that this mRNA is the critical HSFY transcript.…”

Spermatocyte-specific expression of constitutively active heat shock factor 1 induces HSP70i-resistant apoptosis in male germ cells

“…More recently, HSF-similar factor HSFY, which is expressed predominantly in testis, has been discovered. 32,33 Under physiological conditions HSF1 exists as an inactive monomer, while trimerization of HSF1 takes place in response to cellular stress and the trimer binds cisacting DNA sequences termed heat shock elements (HSEs) (reviewed in Fernandes et al 34 ). Activation-induced oligomerization of HSF1 is controlled by intra-and intermolecular hydrophobic interactions mediated by several conserved repeated motifs.…”