摘要:

AbstractIslet‐1 (Isl‐1) is a LIM domain/homeodomain‐type transcription regulator that has been originally identified as an insulin gene enhancer binding protein.Isl‐1is also expressed by subsets of neurons in the central nervous system of rat and chick embryos. We have cloned theIsl‐1cDNA from zebrafish and examined its expression pattern using in situ hybridization to whole‐mount embryos.Isl‐1mRNA first appears immediately after gastrulation in the polster, the cranial ganglia, and in Rohon‐Beard neurons and ventromedial cells of the spinal cord. The expression by the ventromedial cells is segmentally repeated and becomes restricted to the one or two cells slightly anterior to the segment borders. Double staining by in situ hybridization and an antibody which stains most axons suggested that these segmentally distributed cells may be either the rostral primary motoneuron (RoP) or middle primary motoneuron (MiP). This raises a possibility thatIsl‐1may be involved during determination of subtype identities of the primary motoneurons. Furthermore, the specificIsl‐1mRNA expression in the spinal cord is under the control of the somites, since mutant embryo with defective somite failed to maintain this pattern. ©

ISSN:1058-8388    

DOI:10.1002/aja.1001990102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractTo address the role of peptide growth factors in chick organogenesis, we have focused on TGFβ2 and have cloned the chick Type II and Type III TGFβ receptors. The chick Type II receptor is a serine/threonine kinase with a ligand binding profile identical to the human receptor and a divergent N‐terminus when compared to the mammalian receptors. The chick Type III receptor is a betaglycan that demonstrates a binding profile identical to the rat receptor and contains a single transmembrane spanning domain and short cytoplasmic tail that are highly conserved when compared to the mammalian receptors. Both the Type II and Type III TGFβ receptors are coexpressed during chick embryogenesis in the developing heart, lung, and eye, and are developmentally upregulated in parallel in the heart and lung. Levels of both receptor proteins and mRNAs also increase in cardiocytes cultured from different developmental stages, in agreement with the increase in Type II and Type III receptor mRNA levels observed in the developing heart. Although exhibiting different temporal or spatial profiles from the receptors, TGFβ2 is also expressed in the developing heart, lung, and eye. These findings are consistent with recent data indicating that co‐expression of both the Type II and Type III TGFβ receptors is required for high affinity binding of TGFβ2 by the Type II receptor and suggest that TGFβ2 and the Type II and Type III TGFβ receptors participate in heart, lung, and eye development. © 1994 Wil

ISSN:1058-8388    

DOI:10.1002/aja.1001990103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractPatterns ofdecapentaplegic (dpp)transcripts derived from the intact gene were compared to the patterns of transcripts generated by partialdpptransgenes in Drosophila embryos. Sequences closest to thedppcoding regions, thedpphin region, were sufficient to expresslacZ‐tagged mRNA in patterns indistinguishable from the patterns of endogenousdppexpression in the dorsal and terminal cells at the blastoderm stage, in the dorsal ectoderm during germ band elongation, and in narrow stripes of ectodermal cells along the dorsal edge of the ectoderm and at the boundary between the lateral and ventral neurogenic regions during germ band shortening. The latter pattern of expression responded to the segment polarity genesnakedandwingless. However, thesedppsequences were not sufficient to drivelacZ‐tagged mRNA expression in other cells normally expressingdpp, including cells in the gnathal segments, the clypeolabrum, the foregut, the midgut visceral mesoderm, and the hindgut. Two separate regulatory regions were found in thedpphin region. A 479 bp region upstream of the promoter was necessary for the segmented pattern of expression in the lateral ectoderm and for expression in the midgut endoderm. Cis‐acting elements in the 2 kbp second intron directed expression in the dorsal and terminal regions of the blastoderm, acted on a heterologous promoter, the P‐element promoter, and responded to pattern information derived from the maternal effect dorsal/ventral patterning genes. © 1994 Wiley

ISSN:1058-8388    

DOI:10.1002/aja.1001990104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractCalbindin‐D28K, a cytoplasmic calcium‐binding protein located in restricted regions of mature metanephric kidneys, is expressed in a complex manner by kidneys developing in culture. In developing collecting duct, it is present in all regions and is independent of 1,25‐dihydroxy‐vitamin D3[1,25(OH)2D3]. In developing nephrons, its expression is restricted to the most distal end of the growing tubule, commences during differentiation of specialized tubule segments, and depends completely on the presence of 1,25(OH)2D3. The Wolffian ducts of mesonephric kidneys also express calbindin independently of 1,25(OH)2D3, as do the Wolffian duct‐derived connecting tubules, but mesonephric nephrons show no expression of the molecule. By displaying separate tissue‐specific controls for calbindin expression, cultured kidney rudiments offer a very accessible system for investigation of the control mechanisms involved. © 1994 Wil

ISSN:1058-8388    

DOI:10.1002/aja.1001990105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractThis study examined whether satellite cells express an embryonic isoform of myosin upon fusion with hypertrophying muscle fibers. Anterior latissimus dorsi (ALD) muscle hypertrophy was induced in adult chickens by weighting one wing. One and 7 days of wing‐weighting produced significant increases in ALD muscle wet weight and in the number of mature fibers expressing ventricular‐like embryonic (V‐EMB) myosin. V‐EMB myosin expression could be an event during regeneration of fibers injured by overload or part of the hypertrophy process itself. Although there was an increase in both the number of damaged fibers and the number of mature fibers expressing embryonic myosin after wing‐weighting, results from this study suggest that these two events were not necessarily related. The apparent health of fibers expressing V‐EMB myosin and the lack of correlation between the numbers of damaged and V‐EMB myosin positive fibers (r = 0.20) suggest that embryonic myosin expression in mature fibers was likely a feature of the hypertrophy process itself. The appearance of V‐EMB myosin in mature fibers 1 day after wing‐weighting suggests that the change in myosin expression did not involve satellite cells since 24 hr is too short a time to permit more than limited satellite cell fusion. The relationship between satellite cells and embryonic myosin expression was examined more closely by labeling dividing satellite cells and their progeny with 5‐bromo‐2‐deoxyuridine, and then colocalizing labeled myofiber nuclei and embryonic myosin in consecutive transverse sections of hypertrophied ALD muscle. One week of wing‐weighting resulted in marked increases in myofiber nuclear labeling index and myofiber nuclear density compared to contralateral control. V‐EMB myosin was not expressed uniformly throughout individual fibers, but rather in discrete regions of varying length. Many V‐EMB myosin positive regions had a higher labeled nuclear density than V‐EMB myosin negative regions indicating that V‐EMB myosin expression was associated with an accumulation of satellite cell progeny in a restricted area. However, it was also clear that satellite cell progeny were not the sole source of V‐EMB myosin since labeled nuclei were completely absent from 41% of the V‐EMB positive regions. Futhermore, the presence of new nuclei did not result in obligatory expression of embryonic myosin because many V‐EMB negative regions had a high labeled nuclear density. Thus, recently incorporated nuclei arising by satellite cell division are implicated as one, but not the sole source of embryonic myosin in hypertrophying muscle. These observations suggest that the non‐uniform pattern of embryonic myosin expression in hypertrophying muscle resulted from differences in nuclear activity, not necessarily the addit

ISSN:1058-8388    

DOI:10.1002/aja.1001990106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractIn previous studies we have observed that the interdigital tissue of the chick embryo leg bud during the stages previous to interdigital cell death exhibits a considerable chondrogenic potentiality both in vivo and in vitro. In the present investigation we have carried out a variety of experimental manipulations of the chick leg bud at stage 29 to discover possible mechanisms accounting for interdigital ectopic chondrogenesis and extradigit formation. Our results show that the interdigital tissue is capable of forming an extradigit when temporarily isolated microsurgically and regrafted in its original loction and after deletion of one of the adjacent digital primordia, suggesting that developing phalangeal cartilages exercise an inhibitory effect on chondrification in adjoining tissues. Furthermore, and of greater importance, ablation of the primordium of a digit is followed by normal development of the definitive digit if the wound surfaces are suitably apposed. These results reveal a considerable regulatory potentital in the autopodium at advanced stages of development. © 1994 Wiley‐Liss, I

ISSN:1058-8388    

DOI:10.1002/aja.1001990107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

摘要:

AbstractWe report the cloning, sequence analysis, and developmental expression pattern oflim1, a member of the LIM class homeobox gene family in the mouse.lim1cDNA encodes a predicted 406 amino acid protein that is 93% identical with the product of theXenopusLIM class homeobox geneXlim1. We have characterizedlim1expression from day 8.5 post coitum onward. Northern blot analysis of RNA transcripts indicates thatlim1is expressed both during embryogenesis and in the adult brain. Analysis by whole‐mount and section in situ hybridization showslim1expression in the central nervous system from the telencephalon through the spinal cord and in the developing excretory system including pronephric region, mesonephros, nephric duct, and metanephros. In the metanephros,lim1is strongly expressed in renal vesicles and S‐shaped bodies, and transcripts are also detected in the ureteric branches. © 1994 Wiley‐Lis

ISSN:1058-8388    

DOI:10.1002/aja.1001990108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY

ISSN:1058-8388    

DOI:10.1002/aja.1001990109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1994

数据来源: WILEY