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Immunohistochemical analysis of the proapoptotic protein Par-4 in normal rat tissues.
Cell Growth Differ. 1997 Aug; 8(8):881-90.CG

Abstract

Prostate apoptosis response 4 (par-4) is a recently identified gene that encodes a transcription factor, Par-4, with a leucine zipper domain. Par-4 protein is constitutively expressed in various cell lines and is functionally required but not sufficient for apoptosis. Induction of Par-4 in cultured cells is found exclusively during apoptosis, and ectopic overexpression of Par-4 enhances the potency of apoptotic stimuli. Western or Northern blot analysis on mRNA or protein extracts, respectively, from rat organs revealed that the expression of Par-4 was ubiquitous and was not restricted to any specific organ(s). To further identify specific cell types that expressed Par-4, we performed an immunohistochemical analysis of the protein in paraffin-embedded sections of various organs from rats. Our findings indicated that consistent with its proapoptotic role, Par-4 is expressed in apoptotic granulosa cells of atretic ovarian follicles and in terminally differentiated cells, such as the cardiomyocytes, cerebellar Purkinje cells, and pyramidal cells of the hypothalamus. Moreover, testosterone ablation by castration of rats caused an early and transient induction of Par-4 in the ductal cells of the prostate that undergo apoptosis. By contrast, in tissues in which the cells could be visually differentiated from their mature counterparts, Par-4 expression was lowest in the mature cells. This was the case for epithelia of the mammary and the prostate gland in which the basal cells maintained higher protein levels of Par-4 than did the terminally differentiated ductal cells. Similarly, cells of the stratum corneum of the skin and cells on top of the duodenal villi stained less intensely for Par-4 as compared to the stem cells in the stratum basale and at the bottom of the crypts of Lieberkühn, respectively. It is possible that Par-4 has to be down-regulated for successful differentiation in these tissues. Taken together, the widespread expression of Par-4 in various adult cell types underscores the physiological importance of the protein. The observation of constitutive Par-4 expression in the stem cell compartments is inconsistent with the probability of apoptosis per se and can be extended to determine whether Par-4 plays a role in other cellular processes.

Authors+Show Affiliations

Department of Surgery, University of Kentucky, Lexington 40536, USA.No affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info availableNo affiliation info available

Pub Type(s)

Journal Article
Research Support, Non-U.S. Gov't
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

9269897

Citation

Boghaert, E R., et al. "Immunohistochemical Analysis of the Proapoptotic Protein Par-4 in Normal Rat Tissues." Cell Growth & Differentiation : the Molecular Biology Journal of the American Association for Cancer Research, vol. 8, no. 8, 1997, pp. 881-90.
Boghaert ER, Sells SF, Walid AJ, et al. Immunohistochemical analysis of the proapoptotic protein Par-4 in normal rat tissues. Cell Growth Differ. 1997;8(8):881-90.
Boghaert, E. R., Sells, S. F., Walid, A. J., Malone, P., Williams, N. M., Weinstein, M. H., Strange, R., & Rangnekar, V. M. (1997). Immunohistochemical analysis of the proapoptotic protein Par-4 in normal rat tissues. Cell Growth & Differentiation : the Molecular Biology Journal of the American Association for Cancer Research, 8(8), 881-90.
Boghaert ER, et al. Immunohistochemical Analysis of the Proapoptotic Protein Par-4 in Normal Rat Tissues. Cell Growth Differ. 1997;8(8):881-90. PubMed PMID: 9269897.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Immunohistochemical analysis of the proapoptotic protein Par-4 in normal rat tissues. AU - Boghaert,E R, AU - Sells,S F, AU - Walid,A J, AU - Malone,P, AU - Williams,N M, AU - Weinstein,M H, AU - Strange,R, AU - Rangnekar,V M, PY - 1997/8/1/pubmed PY - 1997/8/1/medline PY - 1997/8/1/entrez SP - 881 EP - 90 JF - Cell growth & differentiation : the molecular biology journal of the American Association for Cancer Research JO - Cell Growth Differ VL - 8 IS - 8 N2 - Prostate apoptosis response 4 (par-4) is a recently identified gene that encodes a transcription factor, Par-4, with a leucine zipper domain. Par-4 protein is constitutively expressed in various cell lines and is functionally required but not sufficient for apoptosis. Induction of Par-4 in cultured cells is found exclusively during apoptosis, and ectopic overexpression of Par-4 enhances the potency of apoptotic stimuli. Western or Northern blot analysis on mRNA or protein extracts, respectively, from rat organs revealed that the expression of Par-4 was ubiquitous and was not restricted to any specific organ(s). To further identify specific cell types that expressed Par-4, we performed an immunohistochemical analysis of the protein in paraffin-embedded sections of various organs from rats. Our findings indicated that consistent with its proapoptotic role, Par-4 is expressed in apoptotic granulosa cells of atretic ovarian follicles and in terminally differentiated cells, such as the cardiomyocytes, cerebellar Purkinje cells, and pyramidal cells of the hypothalamus. Moreover, testosterone ablation by castration of rats caused an early and transient induction of Par-4 in the ductal cells of the prostate that undergo apoptosis. By contrast, in tissues in which the cells could be visually differentiated from their mature counterparts, Par-4 expression was lowest in the mature cells. This was the case for epithelia of the mammary and the prostate gland in which the basal cells maintained higher protein levels of Par-4 than did the terminally differentiated ductal cells. Similarly, cells of the stratum corneum of the skin and cells on top of the duodenal villi stained less intensely for Par-4 as compared to the stem cells in the stratum basale and at the bottom of the crypts of Lieberkühn, respectively. It is possible that Par-4 has to be down-regulated for successful differentiation in these tissues. Taken together, the widespread expression of Par-4 in various adult cell types underscores the physiological importance of the protein. The observation of constitutive Par-4 expression in the stem cell compartments is inconsistent with the probability of apoptosis per se and can be extended to determine whether Par-4 plays a role in other cellular processes. SN - 1044-9523 UR - https://www.unboundmedicine.com/medline/citation/9269897/Immunohistochemical_analysis_of_the_proapoptotic_protein_Par_4_in_normal_rat_tissues_ L2 - http://cgd.aacrjournals.org/cgi/pmidlookup?view=long&pmid=9269897 DB - PRIME DP - Unbound Medicine ER -