An Unusual Nucleoporin-Related Messenger Ribonucleic Acid is Present in the Germ Cells of Rat Testis1

Abstract

An mRNA with a substantial similarity to the rat p62 mRNA that encodes a nucleoporin was cloned from the rat testis. A probe derived from a unique sequence in the nucleoporin-related (NPR) cDNA revealed a novel mRNA of 1.3 kb, different from the 2.7-kb transcript attributed to the p62 gene. This 1.3-kb transcript was not detected in Sertoli cells; it was found primarily in the haploid germ cells of the adult testis. The DNA sequencing revealed that the central region of the NPR cDNA sequence was identical to the 3' portion of the p62 cDNA containing heptad repeat sequences. However, the 5' region and the extreme 3' region of the NPR cDNA sequence were different from the p62 cDNA. Interestingly, the extreme 3' untranslated region (UTR) contained a 212-bp inverted repeat of a sequence located in the middle of the NPR cDNA that is identical to the p62 sequence. The inverted repeats of the NPR sequence could potentially hybridize, leading to the formation of circular transcripts. Using antibodies specific for the C-terminal regions of p62, a 26-kDa protein was detected from NPR cDNA hybrid-arrested translational products, and a 28-kDa protein was detected from the testis germ cell extracts but not from Sertoli cell extracts.

Antisperm Antibodies Associated with Infertility: Properties and Encoding Genes of Target Antigens

“…It is interesting to note that a component of human sperm tails has been identified as a nucleoporin‐related protein (110). Moreover, nucleoporin‐related mRNA has been shown to be transcribed in germ cells of rat testis (111).…”

Molecular Cloning and Characterization of a Novel Testis-Specific Nucleoporin-Related Gene

“…Thus far, only one nucleoporin-related mRNA (NPR) has been identified to be present in germ cells of mammalian testis [34]. The present paper describes the first study of identifying and characterizing a nucleoporin-related gene expression in human testis.…”

The nuclear pore complex becomes alive: new insights into its dynamics and involvement in different cellular processes

“…Despite the conserved structural features of NPCs among different species as yeast and vertebrates there have been some reports about cell-type specific expression of certain nucleoporins (Wang et al, 1994;Hu and Gerace, 1998;Nothwang et al, 1998;Cai et al, 2002;Coy et al, 2002;Olsson et al, 2004). For example, RanBP2L1, and POMFIL1 represent cell-type specific expressed proteins with homology to the nucleoporins RanBP2/Nup358 and POM121 which are coded by different genes (Wang et al, 1994;Nothwang et al, 1998;Cai et al, 2002;Coy et al, 2002). In contrast, the differentially expressed nucleoporins Nup45 and Nup58, both constituents of the Nup62 NPC subcomplex, seem to be generated by alternative splicing from the same gene (Hu and Gerace, 1998).…”