scholarly journals Mammalian aromatases

Reproduction ◽  
2001 ◽  
pp. 685-695 ◽  
Author(s):  
A Conley ◽  
M Hinshelwood
Keyword(s):  
Cytochrome P450 ◽  
Enzyme System ◽  
Well Being ◽  
Enzyme Complex ◽  
Specific Expression ◽  
Aromatase Expression ◽  
Important Species ◽  
Tissue Specific ◽  
Essential Components ◽  
Species Specific

Aromatase is the enzyme complex that catalyses the synthesis of oestrogens from androgens, and therefore it has unique potential to influence the physiological balance between the sex steroid hormones. Both aromatase cytochrome P450 (P450arom) and NADPH-cytochrome P450 reductase (reductase), the two essential components of the enzyme complex, are highly conserved among mammals and vertebrates. Aromatase expression occurs in the gonads and brain, and is essential for reproductive development and fertility. Of interest are the complex mechanisms involving alternative promoter utilization that have evolved to control tissue-specific expression in these tissues. In addition, in a number of species, including humans, expression of aromatase has a broader tissue distribution, including placenta, adipose and bone. The relevance of oestrogen synthesis and possibly androgen metabolism in these peripheral sites of expression is now becoming clear from studies in P450arom knockout (ArKO) mice and from genetic defects recognized recently in both men and women. Important species differences in the physiological roles of aromatase expression are also likely to emerge, despite the highly conserved nature of the enzyme system. The identification of functionally distinct, tissue-specific isozymes of P450arom in at least one mammal, pigs, and several species of fish indicates that there are additional subtle, but physiologically significant, species-specific roles for aromatase. Comparative studies of mammalian and other vertebrate aromatases will expand understanding of the role played by this ancient enzyme system in the evolution of reproduction and the adaptive influence of oestrogen synthesis on general health and well being.

scholarly journals Role of DNA methylation in the tissue-specific expression of the CYP17A1 gene for steroidogenesis in rodents

2009 ◽  
Vol 202 (1) ◽  
pp. 99-109 ◽  
Author(s):  
Elika Missaghian ◽  
Petra Kempná ◽  
Bernhard Dick ◽  
Andrea Hirsch ◽  
Rasoul Alikhani-Koupaei ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Histone Deacetylase Inhibitors ◽  
Cpg Island ◽  
Specific Expression ◽  
Tissue Specific ◽  
Adrenal Cells ◽  
Tissue Specific Expression ◽  
As Species ◽  
Species Specific

The CYP17A1 gene is the qualitative regulator of steroidogenesis. Depending on the presence or absence of CYP17 activities mineralocorticoids, glucocorticoids or adrenal androgens are produced. The expression of the CYP17A1 gene is tissue as well as species-specific. In contrast to humans, adrenals of rodents do not express the CYP17A1 gene and have therefore no P450c17 enzyme for cortisol production, but produce corticosterone. DNA methylation is involved in the tissue-specific silencing of the CYP17A1 gene in human placental JEG-3 cells. We investigated the role of DNA methylation for the tissue-specific expression of the CYP17A1 gene in rodents. Rats treated with the methyltransferase inhibitor 5-aza-deoxycytidine excreted the cortisol metabolite tetrahydrocortisol in their urine suggesting that treatment induced CYP17 expression and 17α-hydroxylase activity through demethylation. Accordingly, bisulfite modification experiments identified a methylated CpG island in the CYP17 promoter in DNA extracted from rat adrenals but not from testes. Both methyltransferase and histone deacetylase inhibitors induced the expression of the CYP17A1 gene in mouse adrenocortical Y1 cells which normally do not express CYP17, indicating that the expression of the mouse CYP17A1 gene is epigenetically controlled. The role of DNA methylation for CYP17 expression was further underlined by the finding that a reporter construct driven by the mouse −1041 bp CYP17 promoter was active in Y1 cells, thus excluding the lack of essential transcription factors for CYP17 expression in these adrenal cells.

scholarly journals Duplicated flavonoid 3’-hydroxylase and flavonoid 3’, 5’-hydroxylase genes in barley genome

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e6266 ◽  
Author(s):  
Alexander V. Vikhorev ◽  
Ksenia V. Strygina ◽  
Elena K. Khlestkina
Keyword(s):  
Cytochrome P450 ◽  
Anthocyanin Biosynthesis ◽  
Gene Families ◽  
Gene Copy ◽  
Aleurone Layer ◽  
Specific Expression ◽  
Tissue Specific ◽  
Barley Genome ◽  
Tissue Specific Expression ◽  
Different Parts

Background Anthocyanin compounds playing multiple biological functions can be synthesized in different parts of barley (Hordeum vulgare L.) plant. The diversity of anthocyanin molecules is related with branching the pathway to alternative ways in which dihydroflavonols may be modified either with the help of flavonoid 3′-hydroxylase (F3′H) or flavonoid 3′,5′-hydroxylase (F3′5′H)—the cytochrome P450-dependent monooxygenases. The F3′H and F3′5′H gene families are among the least studied anthocyanin biosynthesis structural genes in barley. The aim of this study was to identify and characterise duplicated copies of the F3′H and F3′5′H genes in the barley genome. Results Four copies of the F3′5′H gene (on chromosomes 4HL, 6HL, 6HS and 7HS) and two copies of the F3′H gene (on chromosomes 1HL and 6HS) were identified in barley genome. These copies have either one or two introns. Amino acid sequences analysis demonstrated the presence of the flavonoid hydroxylase-featured conserved motifs in all copies of the F3′H and F3′5′H genes with the exception of F3′5′H-3 carrying a loss-of-function mutation in a conservative cytochrome P450 domain. It was shown that the divergence between F3′H and F3′5′H genes occurred 129 million years ago (MYA) before the emergence of monocot and dicot plant species. The F3′H copy approximately occurred 80 MYA; the appearance of F3′5′H copies occurred 8, 36 and 91 MYA. qRT-PCR analysis revealed the tissue-specific activity for some copies of the studied genes. The F3′H-1 gene was transcribed in aleurone layer, lemma and pericarp (with an increased level in the coloured pericarp), whereas the F3′H-2 gene was expressed in stems only. The F3′5′H-1 gene was expressed only in the aleurone layer, and in a coloured aleurone its expression was 30-fold higher. The transcriptional activity of F3′5′H-2 was detected in different tissues with significantly higher level in uncoloured genotype in contrast to coloured ones. The F3′5′H-3 gene expressed neither in stems nor in aleurone layer, lemma and pericarp. The F3′5′H-4 gene copy was weakly expressed in all tissues analysed. Conclusion F3′H and F3′5′H-coding genes involved in anthocyanin synthesis in H. vulgare were identified and characterised, from which the copies designated F3′H-1, F3′H-2, F3′5′H-1 and F3′5′H-2 demonstrated tissue-specific expression patterns. Information on these modulators of the anthocyanin biosynthesis pathway can be used in future for manipulation with synthesis of diverse anthocyanin compounds in different parts of barley plant. Finding both the copies with tissue-specific expression and a copy undergoing pseudogenization demonstrated rapid evolutionary events tightly related with functional specialization of the duplicated members of the cytochrome P450-dependent monooxygenases gene families.

Tissue-specific promoters regulate aromatase cytochrome P450 expression

1993 ◽  
Vol 39 (2) ◽  
pp. 317-324 ◽  
Author(s):  
E R Simpson ◽  
M S Mahendroo ◽  
G D Means ◽  
M W Kilgore ◽  
C J Corbin ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Fetal Liver ◽  
Start Site ◽  
Specific Expression ◽  
Tissue Specific ◽  
Translational Start Site ◽  
Fetal Tissues ◽  
Translational Start ◽  
A Minor ◽  
Estrogen Biosynthesis

Abstract In humans, estrogen biosynthesis occurs in several tissue sites, including ovary, placenta, adipose, and brain. Recent work from our laboratory indicates that tissue-specific expression of aromatase cytochrome P450 (P450arom), the enzyme responsible for estrogen biosynthesis, is determined, in part, by the use of tissue-specific promoters. Thus, the expression of P450arom in human ovary appears to utilize a promoter proximal to the translation start site. This promoter is not utilized in placenta; instead, the promoter used to drive aromatase expression in placenta is > or = 40 kb upstream from the translational start site. In addition, a minor promoter used in the expression of a small proportion of placental transcripts is 9 kb upstream from the start of translation. Transcripts from these promoters are also expressed in other fetal tissues, including placenta-related cells such as JEG-3 choriocarcinoma cells and hydatidiform moles and other fetal tissues such as fetal liver. In adipose tissue, on the other hand, expression of P450arom may be achieved by yet another, adipose-specific promoter. The various 5'-untranslated exons unique for expression driven by each of these promoters are spliced into a common intron/exon boundary upstream from the translational start site. This means that the protein expressed in each of the various tissue-specific sites of estrogen biosynthesis is identical.

Multiplicity and tissue specific expression of camel cytochrome P450(s)

1998 ◽  
Vol 121 (1-3) ◽  
pp. 205-211 ◽  
Author(s):  
Haider Raza ◽  
Annie John ◽  
Mohammad S Lakhani ◽  
Ijaz Ahmed ◽  
William Montague
Keyword(s):  
Cytochrome P450 ◽  
Specific Expression ◽  
Tissue Specific ◽  
Tissue Specific Expression

Tissue-specific expression patterns of nuclear receptors

2013 ◽  
Author(s):  
AL Bookout ◽  
Y Jeong ◽  
M Downes ◽  
RT Yu ◽  
RM Evans ◽  
...  
Keyword(s):  
Nuclear Receptors ◽  
Expression Patterns ◽  
Specific Expression ◽  
Tissue Specific ◽  
Tissue Specific Expression

Matrix metalloproteinases in stroke

2017 ◽  
pp. 110-117
Author(s):  
А.А. Пальцын
Keyword(s):  
Matrix Metalloproteinases ◽  
Enzyme System ◽  
Enzyme Complex ◽  
Pathogenic Factors ◽  
Pathogenic Action ◽  
Activity Of Enzymes ◽  
Living Tissues ◽  
Current Reconstruction ◽  
Metalloproteinase Activity

Матриксные металлопротеиназы - ферментный комплекс, необходимый для сохранения гомеостаза. Он участник нормальной, постоянно текущей реконструкции всех живых тканей. Действие патогенных факторов нарушает слаженную работу этого комплекса. Часто нарушение выражается излишней активностью ферментов, усиливающей патогенное действие. Однако и заживление, форсированное новообразование тканевых элементов, может происходить только при повышенной, в сравнении с нормой, активности металлопротеиназ. Такая ситуация требует от медицины умения разумно вмешиваться в работу ферментной системы. В статье представлены некоторые результаты этих вмешательств. Matrix metalloproteinases - enzyme complex necessary for maintenance of the homeostasis. He is a participant of normal, constantly current reconstruction of all living tissues. Action of pathogenic factors breaks harmonious work of this complex. Often violation is expressed by the excessive activity of enzymes amplifying pathogenic action. However and healing, which is accelerated new growth of tissue elements, can happen only at raised, compared with norm, metalloproteinase activity. Such situation demands from medicine of ability participate reasonably in work of enzyme system. The article presents some of the results of these actions.

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