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The health profile of cloned animals. 总被引:17,自引:0,他引:17
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Elizabeth Storer Scholl Antonella Pirone Daniel H Cox R Keith Duncan Michele H Jacob 《Channels (Austin, Tex.)》2014,8(1):62-75
Small conductance Ca2+-sensitive potassium (SK2) channels are voltage-independent, Ca2+-activated ion channels that conduct potassium cations and thereby modulate the intrinsic excitability and synaptic transmission of neurons and sensory hair cells. In the cochlea, SK2 channels are functionally coupled to the highly Ca2+ permeant α9/10-nicotinic acetylcholine receptors (nAChRs) at olivocochlear postsynaptic sites. SK2 activation leads to outer hair cell hyperpolarization and frequency-selective suppression of afferent sound transmission. These inhibitory responses are essential for normal regulation of sound sensitivity, frequency selectivity, and suppression of background noise. However, little is known about the molecular interactions of these key functional channels. Here we show that SK2 channels co-precipitate with α9/10-nAChRs and with the actin-binding protein α-actinin-1. SK2 alternative splicing, resulting in a 3 amino acid insertion in the intracellular 3′ terminus, modulates these interactions. Further, relative abundance of the SK2 splice variants changes during developmental stages of synapse maturation in both the avian cochlea and the mammalian forebrain. Using heterologous cell expression to separately study the 2 distinct isoforms, we show that the variants differ in protein interactions and surface expression levels, and that Ca2+ and Ca2+-bound calmodulin differentially regulate their protein interactions. Our findings suggest that the SK2 isoforms may be distinctly modulated by activity-induced Ca2+ influx. Alternative splicing of SK2 may serve as a novel mechanism to differentially regulate the maturation and function of olivocochlear and neuronal synapses. 相似文献
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Hatchery selection promotes boldness in newly hatched brown trout (Salmo trutta): implications for dominance 总被引:2,自引:0,他引:2
Sundstrom L. Fredrik; Petersson Erik; Hojesjo Johan; Johnsson Jorgen I.; Jarvi Torbjorn 《Behavioral ecology》2004,15(2):192-198
By using newly hatched (approximately 2 weeks old) brown trout(Salmo trutta) from six families of wild and six families ofsea-ranched origin (seventh generation), we tested the hypothesesthat (1) the hatchery environment selects for increased boldness,and (2) boldness predicts dominance status. Sea-ranched troutspend their first 2 years in the hatchery before being releasedinto the wild at the onset of seaward migration. Trout werepresented with a novel object (tack) and with food (brine shrimp),and their responses were measured and scored in terms of boldness.Siblings with increasing difference in boldness were then pairedin dyadic contests. Fish of sea-ranged origin were on averagebolder than were fish of wild origin, and bolder individualswere more likely to become dominant regardless of origin. Boldnesswas not related to RNA levels, indicating that bold behaviorwas not a consequence of higher metabolism or growth rate. Neitherwas size a predictor of bold behavior or the outcome of dyadiccontests. These results are consistent with studies on olderlife stages showing increased boldness toward predators in hatchery-selectedfish, which suggests that behavioral consequences of hatcheryselection are manifested very early in life. The concordancebetween boldness and dominance may suggest that these behaviorsare linked in a risk prone-aggressive phenotype, which may bepromoted by hatchery selection. However, we also found significantvariation in behavioral and growth-related traits among families,suggesting that heritable variation has not been exhausted bysea-ranching procedures. 相似文献
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Keith G. Danielson Janice E. Knepper Frances S. Kittrell Janet S. Butel Daniel Medina Elisa M. Durban 《In vitro cellular & developmental biology. Plant》1989,25(6):535-543
Summary Clonal populations were isolated from the mouse mammary cell line, COMMA-D, by transfection with a dominant-selectable gene,
pSV2Neo, which confers resistance to the antibiotic, G418. Seven of twenty-four clones isolated retained the ability of the
parental line to repopulate cleared mammary fat pads in vivo as ductal-alveolar hyperplasias. Two sublines designated CDNR2
and CDNR4 retained hyperplastic growth potential after multiple passages in vitro with low incidence of tumor formation. A
third subpopulation, CDNR1, contained a single integration site for the pSV2Neo plasmid indicating a bonafide clonal origin
for this subline. CDNR1 cells displayed heterogeneous growth phenotypes in vivo including hyperplasia, adenocarcinoma, and
bone formation. Functional differentiation of CDNR1 cells organized as alveolarlike structures in vivo or on floating collagen
gels in vitro was observed as determined by immunoperoxidase staining for the milk-specific protein, casein. Overall, the
results indicate that a subset of cells from the COMMA-D cell line may be functionally analogous to stem cells existing in
the mammary gland.
Supported by NCI research grants CA-38650, CA-33369, CA-39017, and CA-25215. 相似文献
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