Transition Protein 1 (TNP1)

TP1; STP-1; During Histone To Protamine Replacement; Spermatid nuclear transition protein 1

SPN	Q989
HGNC	11951
MGI	98784
PubMed	2249851
RGD	3884
UniProt	P09430

Transition protein-1 is a spermatid-specific product of the haploid genome which replaces histone and is itself replaced in the mature sperm by the protamines. Yu et al. (2000) generated mice lacking the major transition nuclear protein, TP1, by targeted deletion of the Tnp1 gene in mouse embryonic stem cells. Surprisingly, testis weights and sperm production were normal in the mutant mice, and only subtle abnormalities were detected in sperm morphology.

Electron microscopy showed large rod-like structures in the chromatin of mutant step 13 spermatids, in contrast to the fine chromatin fibrils observed in wildtype. Steps 12-13 spermatid nuclei from the testis of Tnp1-null mice contained, in place of TP1, elevated levels of TP2 (TNP2) and some PRM2 precursor.

Reference

"The nucleotide sequence of human transition protein 1 cDNA."
Nucleic Acids Res. 16:7723-7723(1988) [PubMed] [Europe PMC] [Abstract]

"Nucleotide sequence of the gene for human transition protein 1 and its chromosomal localization on chromosome 2."
Genomics 8:324-330(1990) [PubMed] [Europe PMC] [Abstract]

"The status, quality, and expansion of the NIH full-length cDNA project: the Mammalian Gene Collection (MGC)."
Genome Res. 14:2121-2127(2004) [PubMed] [Europe PMC] [Abstract]

"Expression of mRNA and protein of nucleoproteins during human spermiogenesis."
Mol. Hum. Reprod. 4:939-945(1998) [PubMed] [Europe PMC] [Abstract]