Disease relevance of Pem

• This promoter normally drives the expression of the Pem homeobox gene in specific cell types in ovary and placenta but is aberrantly expressed in lymphomas, neuroblastomas, retinoblastomas, carcinomas, and sarcomas [1].

High impact information on Pem

• Localization and stability of introns spliced from the Pem homeobox gene [2].
• By using a tetracycline (tet)-regulated promoter, we found that the half-lives of these Pem introns ranged from 9 to 29 min, comparable with those of short lived mRNAs such as those encoding c-fos and c-myc [2].
• We show that the rat Pem genomic structure includes three 5'-untranslated (5'-UT) exons and four coding exons, three of which encode the homeodomain [3].
• The Pem homeobox gene. Androgen-dependent and -independent promoters and tissue-specific alternative RNA splicing [3].
• Rhox5 (previously called Pem), the founding member of a homeobox gene cluster that we recently identified on the X chromosome, is selectively expressed in granulosa cells in the ovary and other somatic-cell types in other reproductive organs [4].

Biological context of Pem

• We found that Rhox5 expression in the ovary is governed by the Rhox5 distal promoter and is expressed at least as early as Day 5 postpartum [4].
• The discovery that Rhox5 expression in granulosa cells is regulated by MAPK pathways and ETS and SP1 family members provides an opportunity to understand how these regulatory pathways and factors collaborate to regulate gene expression during the ovarian cycle [4].
• Rhox5 mRNA levels are regulated during the ovarian cycle, peaking before ovulation [4].
• This indicates either that spliced Pem introns are uniquely exported to the cytoplasm for degradation or they reside in a unique soluble nuclear fraction [2].
• Here, we report that a processed gene on rat chromosome 4 that is highly related to the X chromosome-encoded rat Pem (r.Pem) homeobox gene is transcriptionally active [5].

Anatomical context of Pem

• Subcellular fractionation analysis revealed that spliced Pem introns and pre-mRNA accumulated in the nuclear matrix, high salt-soluble, and DNase-sensitive fractions within the nucleus [2].
• In the testis, Pem mRNA levels were elevated earlier (between Days 12 and 15 postpartum) and less dramatically than in epididymis [6].
• Pem gene expression was primarily confined to reproductive tissue: epididymis, testis, ovary, and placenta [6].
• In the epididymis, Pem transcripts were localized by in situ hybridization analysis to the proximal cauda region, a site where spermatozoa gain fertilization competence [6].
• More recently, it has been shown that the orphan homeobox gene, Pem, originally isolated by subtraction hybridization on the basis of its differential expression in tumor cell lines, is selectively expressed in reproductive tissue [7].

Associations of Pem with chemical compounds

• Pem mRNA levels dramatically increased between Days 21 and 26 postpartum in the epididymis, coincident with the induction of genes known to be responsive to testosterone (T), but in contrast to that of other genes examined, including the Hoxc-8 homeobox gene [6].

Analytical, diagnostic and therapeutic context of Pem

• Pem gene expression in the testis was depressed after hypophysectomy, but normal levels of Pem expression were not restored by T treatment under the same conditions that permitted normal Pem expression in the epididymis [6].

References