A unique variant of a homeobox gene related to Drosophila cut is expressed in mouse testis.
Mammalian homologues of the Drosophila cut homeobox gene encode transcriptional repressors that are involved in tissue-specific and developmental gene regulation. We examined the expression of a murine cut homologue (Cux-1) in the adult mouse. In many somatic tissues, Cux-1 was expressed as a 13-kb transcript. However, the highest expression of Cux-1 was in the testis, where a unique 2.4-kb splice variant was identified. Less abundant transcripts of 5 kb, 6.5 kb, and 8.5 kb were also detected only in the testis. The nucleotide sequence of the 2.4-kb Cux-1 transcript was identical to the 13-kb transcript in the region of overlap, but the testis-specific transcript encoded a truncated protein that contained only one Cut repeat in addition to the Cut-related homeodomain. Studies of mice homozygous for the atrichosis (at/at) mutation suggested that the 2.4-kb transcript was expressed in germ cells in the testis. In situ hybridization verified that Cux-1 was transiently expressed in post-meiotic germ cells at the round spermatid stage. Immunoblot analysis of nuclear extracts showed that the testis-specific Cux-1 transcripts encoded a 55-kDa protein. These results demonstrate that multiple products of a cut-related homeobox gene are expressed in the testis. The highly restricted pattern of expression of Cux-1 in the testis suggests that it may be involved in regulation of postmeiotic gene expression.
Vanden Heuvel
G B
GB
Department of Internal Medicine, Yale University School of Medicine, New Haven, Connecticut 06520, USA.
Quaggin
S E
SE
Igarashi
P
P
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D003001:Cloning, Molecular; D004330:Drosophila / Q000235:genetics; D029721:Drosophila Proteins; D015870:Gene Expression / Q000235:genetics*; D005801:Genes, Homeobox / Q000235:genetics*; D018398:Homeodomain Proteins; D007301:Insect Hormones / Q000737:chemistry / Q000235:genetics*; D008297:Male; D051379:Mice; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000737:chemistry / Q000235:genetics*; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics*; D013737:Testis / Q000033:anatomy & histology / Q000502:physiology*; D014157:Transcription Factors
D029721:Drosophila Proteins; D018398:Homeodomain Proteins; D007301:Insect Hormones; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; D014157:Transcription Factors; C066381:ct protein, Drosophila