title: Mutations in SOHLH1 gene associate with nonobstructive azoospermia.
abstract: In a previous study, we found SOHLH1 (spermatogenesis and oogenesis-specific basic helix-loop-helix 1) as the first testis-specific basic helix-loop-helix transcription factor essential for spermatogonial differentiation. SOHLH1 therefore represents an excellent candidate gene for testicular failure such as nonobstructive azoospermia (NOA). We analyzed whether there were mutations in the SOHLH1 gene in 96 Korean patients with NOA. The sequence analysis discovered three novel variations: one intronic variant (c.346-1G>A), and two nonsynonymous exonic variants (c.91T>C and c.529C>A) with known single nucleotide polymorphisms (SNPs), which included six intronic variants, two synonymous, and two nonsynonymous variants. We examined the consequences of mutations in SOHLH1 using in vivo and in vitro assays. Analysis of transcripts from minigenes carrying the c.346-1G>A revealed that splicing site variation leads to the partial deletion at a cryptic splicing site within exon 4. This deletion results in SOHLH1 with a truncated bHLH domain. Transient transfection assay showed that the SOHLH1 mutant with the truncated domain disrupted the transcriptional activity of KIT promoter, whereas two missense mutations harboring either p.Arg37Gln or p.Pro269Ser did not have a significant effect on its transactivation. Our findings indicate that a splice-acceptor site mutation that probably causes a nonfunctional SOHLH1 protein results in nonobstructive azoospermia by the lack of normal spermatogenesis.
authors.affiliation: Department of Biomedical Science, CHA University, Seoul, Republic of Korea. shshim@cha.ac.kr
authors.forename: Youngsok
authors.initials: Y
authors.lastname: Choi
authors.forename: Sanghyun
authors.initials: S
authors.lastname: Jeon
authors.forename: Mikyung
authors.initials: M
authors.lastname: Choi
authors.forename: Min-ho
authors.initials: MH
authors.lastname: Lee
authors.forename: Miseon
authors.initials: M
authors.lastname: Park
authors.forename: Dong Ryul
authors.initials: DR
authors.lastname: Lee
authors.forename: Kyu-Yeon
authors.initials: KY
authors.lastname: Jun
authors.forename: Youngjoo
authors.initials: Y
authors.lastname: Kwon
authors.forename: Ok-Hee
authors.initials: OH
authors.lastname: Lee
authors.forename: Seung-Hun
authors.initials: SH
authors.lastname: Song
authors.forename: Ji-Young
authors.initials: JY
authors.lastname: Kim
authors.forename: Kyung-Ah
authors.initials: KA
authors.lastname: Lee
authors.forename: Tae Ki
authors.initials: TK
authors.lastname: Yoon
authors.forename: Aleksandar
authors.initials: A
authors.lastname: Rajkovic
authors.forename: Sung Han
authors.initials: SH
authors.lastname: Shim
mesh_terms: D000328:Adult; D000595:Amino Acid Sequence; D053713:Azoospermia / Q000235:genetics*; D001483:Base Sequence; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics*; D002460:Cell Line; D004252:DNA Mutational Analysis; D005091:Exons / Q000235:genetics; D005260:Female; D017353:Gene Deletion; D020022:Genetic Predisposition to Disease; D006801:Humans; D007438:Introns / Q000235:genetics; D008156:Luciferases / Q000235:genetics / Q000378:metabolism; D008297:Male; D008969:Molecular Sequence Data; D009154:Mutation; D010375:Pedigree; D020641:Polymorphism, Single Nucleotide; D022821:RNA Splice Sites / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D013737:Testis / Q000378:metabolism / Q000473:pathology; D014162:Transfection
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D008156:Luciferases; D022821:RNA Splice Sites; C552401:SOHLH1 protein, human