Molecular cloning, functional analysis, and RNA expression analysis of zfCx45.6 : a zebrafish cardiovascular connexin
Bibliographic record
Abstract
Gap junctions are intercellular channels that allow the direct exchange of molecules up to about 1200 Daltons in size.Six connexins join together to form a hemichannel termed a connexon, and two connexons from different cells dock to form an aqueous channel.A gap junction is formed by the aggregation of hundreds of these channels into plaques.Gap junctions fuirction in a variety of biological processes such as tissue homeostasis, embryonic development, and tumorigenesis.In the verlebrate cardiovascular system, gap junctions function in intercellular communication essential for the co-ordinated propagation of the heartbeat, and the control of vasomotor responses in the vascular system.In this study, a connexin gene encoding a polypeptide of 400 amino acids, with a molecular weight of 45.6 kDa, was cloned from zebrafish genomic DNA.Accordingly, tlre connexin was named zfCx45.6.ZfCx45.6 exhibits 53Yo amino acid identity to chick Cx42 which is expressed in the cardiovascular system.With the use of the LN54 radiation hybrid panel, zfCx45.6 was mapped to zebrafish linkage group 9. Northern blots and RT-PCR revealed the presence of zfCx45.6 mRNA in the embryo before2 lrours post fertilization (hpf), and then againbeginning at about 12hpf, after which time no major changes in expression levels were detected.In the adult, zfCx45.6 6RNA continued to be detected in the heart, as well as the brain, liver and ovary, but not the lens.Whole mount in-situ hybridization revealed zfCx45.6 mRNA r,vas highly expressed in the major vasculature of the entire embryo, and to a lesser extent in the heart.The zebrafish (Danio rerio) is an excellent model system to study cardiovascular developrnent, in part due to its large, externally developing, optically transparent elnbryos, and the fact that early development can occur in the absence of functional circulation.With the previous isolation of zebrafish Cx43 and Cx43.4,zebrafishorthologues have now been isolated for tluee of the four comexins expressed in the mammalian cardiovascular system.With the advent of antisense technologies and methods allowing for the measurement of many cardiovascular functions in minute anitnals and embryos, these studies lay the groundwork for future studies on the role of connexins in the developing and mature vertebrate cardiovascular system using the zebrahsh model system.as a student in his lab.Witli his advice and support I have learned a great deal over the last few years.I would also like to thank the other members of rny thesis committee, Elissavet Kardami and Ross McGowan, for their insight and suggestions.Thanks to all the students who have been in (and through) the lab, especially Slraohong andLiz' Their comments and discussions, whether related to lab material or not, tnade working in the lab a thoroughly enjoyable experience.Special thanks to Roxane for the weekly meetings.Most of all, I would like to thank rny friends, farnily and loved ones.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.002 | 0.001 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".