164. THE IMPRINT STATUS AND EXPRESSION OF INS IN THE TAMMAR WALLABY, MACROPUS EUGENII

2009 ◽  
Vol 21 (9) ◽  
pp. 82
Author(s):  
J. M. Stringer ◽  
G. Shaw ◽  
A. Pask ◽  
M. B. Renfree
Keyword(s):  
Mammary Gland ◽  
Genomic Imprinting ◽  
Direct Sequencing ◽  
Tammar Wallaby ◽  
Epigenetic Mechanism ◽  
Macropus Eugenii ◽  
Parental Allele ◽  
Absolute Requirement ◽  
Lactation Phase

Genomic imprinting is an epigenetic mechanism that differentially regulates the expression of certain genes, resulting in expression from only one parental allele. It is presumed to have first evolved after the divergence of therian mammals from the monotremes. One imprinted gene, INS is maternally imprinted (paternally expressed) in the eutherian and marsupial yolk sac1,2. INS encodes the precursor to the hormone insulin, which regulates carbohydrate metabolism and has a role in cell growth and, by regulating amino acid and fatty acid transporters, protein synthesis. In rats, mice and several other mammals insulin, in addition to cortisol and prolactin, is an absolute requirement for the onset of lactation and the synthesis of milk3. As imprinting plays an important role in regulating nutrition and growth the role of imprinted genes in the placenta has been the focus for imprinting research. Since the mammary gland provides a critical source of nutrition for the neonate in all mammals it is possible that genomic imprinting may have developed and been maintained in this organ. Given that marsupials deliver tiny, altricial young, it is in the relatively long and complex lactation phase where the mother has most control of the young's growth. Therefore, there may be greater selection for genomic imprinting in the marsupial mammary gland than in the eutherian mammary gland. This study examined the expression and the imprint status of INS in the mammary gland and neonatal tissues of the tammar wallaby, Macropus eugenii. INS expression was detected using PCR and direct sequencing provides evidence of INS imprinting in the mammary gland. This is the first study to identify imprinting in the mammary gland of a marsupial and the first to identify INS imprinting outside of the yolk sac.

137. GENOMIC IMPRINTING IN THE MARSUPIAL MAMMARY GLAND

2010 ◽  
Vol 22 (9) ◽  
pp. 55
Author(s):  
J. M. Stringer ◽  
G. Shaw ◽  
A. Pask ◽  
M. B. Renfree
Keyword(s):  
Mammary Gland ◽  
Genomic Imprinting ◽  
Mammary Epithelial Cells ◽  
Direct Sequencing ◽  
Phase 1 ◽  
Tammar Wallaby ◽  
Yolk Sac ◽  
Epigenetic Mechanism ◽  
Differentially Methylated Region ◽  
Parental Allele

Genomic imprinting is an epigenetic mechanism that differentially regulates the expression of certain genes, resulting in expression from only one parental allele. In mammals, genomic imprinting occurs in the placenta of both eutherians and marsupials, and plays an important role in regulating nutrition and growth of the developing fetus. The mammary gland also provides a critical source of nutrition for the neonate in all mammals, but there are few imprinting studies of this organ. Marsupials deliver tiny, altricial young that complete development during an extended lactation. INS (insulin) is paternally expressed in the eutherian and marsupial yolk sac and curiously is the only gene that is solely imprinted in this organ (1, 2). Insulin regulates carbohydrate metabolism, protein synthesis and cell growth. Insulin, (plus cortisol and prolactin) is required for the onset of lactation and the synthesis of milk (3). We characterised INS expression and examined its imprint status in the mammary gland of the tammar wallaby. INS mRNA is expressed in the mammary gland of the tammar from birth and throughout of lactation with highest expression at the initiation of lactation (Phase 1-2a) and around Phase 3 of lactation. Direct sequencing of 7 individuals at various stages of lactation confirmed that INS is imprinted in the mammary gland. Surprisingly, INS may also be imprinted in several other organs in the adult and juvenile wallaby. Preliminary bisulfite sequencing suggests there is a differentially methylated region located upstream of INS which may help to regulate INS expression. This is the first study to identify INS imprinting outside the yolk sac. As INS is critical for lactation, this is also the first indication that genomic imprinting may regulate lactation, suggesting that imprinting in the mammary gland may be as critical for post-natal survival as placental imprinting is for pre-natal development. (1) Deltour LX, et al. (1995). Tissue- and developmental stage-specific imprinting of the mouse proinsulin gene, Ins2. Dev Biol 168(2): 686–688.(2) Ager EI, et al. (2007). Insulin is imprinted in the placenta of the marsupial, Macropus eugenii. Dev Biol 309: 317–328.(3) Bolander FF, et al. (1981). Insulin is essential for accumulation of casein mRNA in mouse mammary epithelial cells. Proc Natl Acad Sci USA 78(9): 5682–5684.

PROLACTIN RECEPTORS IN THE MAMMARY GLAND, CORPUS LUTEUM AND OTHER TISSUES OF THE TAMMAR WALLABY, MACROPUS EUGENII

1979 ◽  
Vol 83 (1) ◽  
pp. 79-89 ◽  
Author(s):  
C. SERNIA ◽  
C. H. TYNDALE-BISCOE
Keyword(s):  
Mammary Gland ◽  
Corpus Luteum ◽  
Specific Binding ◽  
Tammar Wallaby ◽  
Binding Activity ◽  
Breeding Cycle ◽  
Macropus Eugenii ◽  
Lactating Mammary Gland ◽  
The Mean ◽  
Ovine Prolactin

SUMMARY Specific binding of radio-iodinated ovine prolactin to subcellular tissue fractions of the tammar wallaby (Macropus eugenii) was investigated. Specific binding was found, in order of decreasing binding activity, in the lactating mammary gland, corpus luteum, corpus albicans, adrenal gland and ovary. Specific binding was absent in kidney, liver, brain and inactive mammary gland. The mean association constant (Ka at 23 °C) was determined as 0·90 × 109, 2·20 × 109, 2·44 × 109, 3·38 × 109 and 10·98 × 1091/mol for mammary gland, adrenal, corpus albicans, corpus luteum and ovary respectively. The mean receptor concentration (N) varied from 92·87 × 10−14 mol/mg protein for the mammary gland to 1·03 × 10−14 mol/mg protein for the ovary. The concentration in the corpus luteum varied between tissue pools collected at different times of the annual breeding cycle. The specificity for prolactin was shown in the mammary gland and corpus luteum by the failure of ovine FSH, LH, GH and TSH to displace 125I-labelled ovine prolactin, whereas it was displaced readily by both ovine and bovine prolactin.

scholarly journals A novel whey protein synthesized only in late lactation by the mammary gland from the tammar (Macropus eugenii)

1987 ◽  
Vol 241 (3) ◽  
pp. 899-904 ◽  
Author(s):  
K R Nicholas ◽  
M Messer ◽  
C Elliott ◽  
F Maher ◽  
D C Shaw
Keyword(s):  
Mammary Gland ◽  
Amino Acid ◽  
Whey Protein ◽  
Sequence Data ◽  
Protein A ◽  
Gel Filtration ◽  
Tammar Wallaby ◽  
Exchange Chromatography ◽  
Macropus Eugenii ◽  
Apparent Homogeneity

A major whey protein which appears in milk from the tammar wallaby (Macropus eugenii) only during the second half of lactation (late lactation protein-A, LLP-A) was purified to apparent homogeneity by ion-exchange chromatography and gel filtration. An Mr of 21,600 +/- 2000 was calculated from its amino acid composition. A computer-based comparison of the sequence of the first 69 amino acid residues with the Atlas of Protein Sequence data base showed no significant homology with known proteins. Antiserum to LLP-A was prepared in rabbits, and single radial immunodiffusion was used to measure the amounts of LLP-A in milk during the first 40 weeks of lactation. LLP-A was first detected at 26 weeks; thereafter its concentration increased abruptly, to reach a maximum of 26 g/l at approx. 36 weeks of lactation. Explants prepared from mammary gland biopsies at 20 and 35 weeks of lactation were exposed to [3H]amino acids for 8 h; immunoprecipitation of tissue extracts showed that, whereas the rate of casein synthesis was the same at both stages of lactation, LLP-A was synthesized only by the 35-week mammary gland.

Daily prolactin pulse inhibits the corpus luteum during lactational quiescence in the marsupial, Macropus eugenii

2013 ◽  
Vol 25 (2) ◽  
pp. 456 ◽  
Author(s):  
L. A. Hinds ◽  
C. H. Tyndale-Biscoe
Keyword(s):  
Corpus Luteum ◽  
Tammar Wallaby ◽  
Marked Contrast ◽  
Previous Conclusion ◽  
Macropus Eugenii ◽  
Rate Limiting Step ◽  
Limiting Step ◽  
Progesterone Synthesis ◽  
Rate Limiting

The corpus luteum (CL) of the tammar wallaby is inhibited by prolactin during lactation and seasonal quiescence. In seasonal quiescence a daily transient pulse of prolactin (PRL) of less than 2 h duration is sufficient to maintain inhibition. We investigated whether the same inhibition applies in lactation and, if so, how. Our results show that inhibition of the CL during lactation is maintained by a transient pulse of prolactin once a day. They also show that the minimum time without a PRL pulse for the CL to escape inhibition is more than 48 h and less than 72 h. Nevertheless, some animals had a longer refractory period than 72 h, which was reflected in a longer interval to the progesterone peak and birth. These results support the previous conclusion that PRL exercises its effect on a rate-limiting step in progesterone synthesis and secretion rate from the CL, which precedes any increase in its mass. Therefore, we conclude that the role of PRL is to act as a luteostatic agent, an effect that is in marked contrast to its luteotrophic effect in many eutherian species, including rodents.

Cloning, cDNA analysis and prolactin-dependent expression of a marsupial alpha-lactalbumin

1990 ◽  
Vol 2 (6) ◽  
pp. 693 ◽  
Author(s):  
C Collet ◽  
R Joseph ◽  
K Nicholas
Keyword(s):  
Mammary Gland ◽  
Protein Conformation ◽  
Northern Blot Analysis ◽  
Tammar Wallaby ◽  
Amino Acid Residues ◽  
Macropus Eugenii ◽  
Cdna Analysis ◽  
Maximal Induction ◽  
Almost All ◽  
Alpha Lactalbumin

The gene for alpha-lactalbumin has been cloned from a tammar wallaby (Macropus eugenii) mammary gland cDNA library. Tammar alpha-lactalbumin has approximately 50 and 30% homology to the alpha-lactalbumins of eutherians at the levels of nucleotide and protein sequence respectively. Comparison of the inferred tammar polypeptide sequence with the sequence of the eutherian proteins reveals extensive divergence at almost all of the non-essential amino acid residues. However, the hydropathy plots of the tammar protein are almost identical to those of eutherian alpha-lactalbumins, suggesting that protein conformation is conserved. The tammar gene encodes a transcript of approximately 975 bases. Northern blot analysis of hormone-stimulated mammary gland explants shows that maximal induction of alpha-lactalbumin mRNA is dependent on prolactin and that expression is not modulated by other hormones that play a role in the initiation of lactation in eutherians.

239. Expression of PAF-R and p53 in the endometrium during entry into and reactivation from diapause in the tammar wallaby

2008 ◽  
Vol 20 (9) ◽  
pp. 39
Author(s):  
J. C. Fenelon ◽  
G. Shaw ◽  
M. B. Renfree
Keyword(s):  
Tammar Wallaby ◽  
Early Embryo ◽  
Human Reproduction ◽  
Embryonic Diapause ◽  
P53 Expression ◽  
Cellular Location ◽  
Macropus Eugenii ◽  
A Cell

Embryonic diapause is widespread amongst mammals, but is especially common in the kangaroos and wallabies. In the tammar, Macropus eugenii, the sequence of endocrine events leading to embryonic diapause and reactivation are well defined and the blastocyst can remain in diapause for up to 11 months without cell division or apoptosis occurring (Renfree and Shaw 2000). The ovarian hormones exert their effects on the blastocyst by alterations in the endometrial secretions, but the molecular cross-talk between the endometrium and blastocyst is unknown. One possible regulator of diapause is the phospholipid PAF, an embryotrophin that acts as a trophic/survival factor for the early embryo (O'Neill 2005) partly by inactivating the expression of p53, a cell cycle inhibitor, via the PI3-K pathway. PAF is released from the tammar endometrium around the time of reactivation from diapause (Kojima et al. 1993). This study examined the expression of PAF-R and p53 in the tammar endometrium at entry into, and reactivation from, diapause. PAF-R and p53 were highly conserved with orthologueues in human and mouse. PAF-R and p53 expression was assessed by RT–PCR and both genes were expressed in the endometrium at all stages examined. Quantitative PCR (QPCR) studies performed for PAF-R in the endometrium show that levels of PAF-R vary depending on the stage examined and appear to be increasing at entry into diapause and decreasing at exit from diapause. Immunohistochemical (IHC) studies are in progress to determine the cellular location of PAF-R in the endometrium and confirm the QPCR results. QPCR and IHC studies are in progress to determine if there is any change in levels of expression or cellular location of p53 between the stages examined and how this relates to PAF-R availability. These results suggest that the control of diapause in the tammar involves interactions between multiple factors. (1) Renfree MB, Shaw G (2000) Diapause. Annu Rev Physiol 62, 353–375 (2) O'Neill C (2005) The role of Paf in embryo physiology. Human Reproduction Update 11, 215–228 (3) Kojima T et. al. (1993) Production and secretion of progesterone in vitro and presence of PAF in early pregnancy of the marsupial, Macropus eugenii. Reproduction Fertility Development 5, 15–25.

Protein synthesis and secretion by the epididymis of the tammar wallaby, Macropus eugenii (Macropodidae: Marsupialia)

1992 ◽  
Vol 4 (5) ◽  
pp. 533 ◽  
Author(s):  
G Chaturapanich ◽  
RC Jones ◽  
J Clulow
Keyword(s):  
Protein Synthesis ◽  
Protein Secretion ◽  
Tammar Wallaby ◽  
Secreted Proteins ◽  
Blood Proteins ◽  
Macropus Eugenii ◽  
Cauda Epididymidis

The objectives were to assess the following in a marsupial: which proteins are synthesized by the different regions of the epididymis and secreted into the lumen of the ductus; the effect of the experimental method on the detection of protein secretion; the role of the testis in regulating the protein synthesis and secretion; and whether any of the secreted proteins may associate with spermatozoa. Samples from untreated animals were collected for examination by perfusing Krebs-bicarbonate through the ductus epididymidis in vivo (microperfusion), and after incorporation of [35S]methionine during incubation of minced duct in vitro. Electrophoresis of the samples showed that the caput and corpus epididymidis (initial segments) secreted most of the proteins that were synthesized and secreted by the epididymal mucosa, and that the cauda epididymidis secreted mainly blood proteins. Also, many more proteins were secreted in vitro than into the microperfusates in vivo, or were found by Jones (1987) in micropuncture samples of epididymal plasma. The synthesis and secretion of five proteins was androgen dependent (M(r) 75,700, 30,000, 18,700, 17,400 and 12,800). Also, the luminal fluids from the testis stimulated the secretion of two proteins (M(r) 46,300 and 36,100) and inhibited the secretion of three proteins (M(r) 43,000, 32,300 and 21,400). Examination of detergent extracts of spermatozoa indicated that they lose three proteins (M(r) 28,000, 30,000 and 47,000) and gain one (M(r) 30,400) during passage through the epididymis. The method of determining protein secretion affected the findings. Protein secretion, its control and its association with spermatozoa are broadly similar in the tammar wallaby to the processes described in eutherian mammals.

scholarly journals Role of the Alternate Pathway of Dihydrotestosterone Formation in Virilization of the Wolffian Ducts of the Tammar Wallaby,Macropus eugenii

Endocrinology ◽  
2006 ◽  
Vol 147 (5) ◽  
pp. 2368-2373 ◽  
Author(s):  
Geoffrey Shaw ◽  
Jane Fenelon ◽  
Michelle Sichlau ◽  
Richard J. Auchus ◽  
Jean D. Wilson ◽  
...  
Keyword(s):  
Tammar Wallaby ◽  
Macropus Eugenii ◽  
Alternate Pathway
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