ANAT2341 Lab 9

Muscle Development

Introduction

This laboratory concerns the development and differentiation of skeletal muscle, muscle stem cells, hypertrophy, fibre type differentiation and plasticity.

I will also be covering the Monday lecture material on Musculoskeletal Development.

Objectives

1. Understand the origin, differentiation and development of skeletal muscle tissue.
2. Know what is meant by patterning, conversion and adult plasticity of muscle fibre type.
3. Develop an understanding of research methods for studying skeletal muscle development and function.

Skeletal Muscle Histology

Terms

anterior tibialis - (tibialis anterior) skeletal muscle situated on the lateral side of the tibia and is a direct flexor of the foot at the ankle-joint.

cis-acting elements - DNA sequences that through transcription factors or other trans-acting elements or factors, regulate the expression of genes on the same chromosome.

enhancer - A cis-regulatory sequence that can regulate levels of transcription from an adjacent promoter. Many tissue-specific enhancers can determine spatial patterns of gene expression in higher eukaryotes. Enhancers can act on promoters over many tens of kilobases of DNA and can be 5' or 3' to the promoter they regulate.

extensor digitorum longus - (EDL) skeletal muscle situated at the lateral part of the front of the leg and extend the phalanges of the toes, and, continuing their action, flex the foot upon the leg.

Gtf2ird1 - General Transcription Factor 2 -I Repeat domain-containing protein 1. OMIM: Gtf2ird1

MusTRD1 - muscle TFII-I repeat domain-containing protein 1.

MyHC - acronym for myosin heavy chain.

myoblast - the undifferentiated mononucleated muscle cell progenitor, which in skeletal muscle fuses to form a myotube, that in turn expresses contractile proteins to form a muscle fibre.

myosin heavy chain - protein forming the thick filament of the sarcomere and the motor for actin-myosin contraction. There are 17 different myosin classes.

myotube - the initial multinucleated cell formed by fusion of myoblasts during skeletal muscle development.

promoter - A regulatory region a short distance upstream from the 5' end of a transcription start site that acts as the binding site for RNA polymerase II. A region of DNA to which RNA polymerase IIbinds in order to initiate transcription.

regulatory sequence - (regulatory region, regulatory area) is a segment of DNA where regulatory proteins such as transcription factors bind preferentially.

soleus - skeletal muscle situated immediately in front of the gastrocnemius and when standing taking its fixed point from below, steadies the leg upon the foot and prevents the body from falling forward.

Troponin - striated muscle contraction is regulated by the calcium-ion-sensitive, multiprotein complex troponin and the fibrous protein tropomyosin. Troponin has 3 subunits (TnC, TnI, TnT) and is located on the actin filament. OMIM: Troponin I slow

visuospatial deficiency - performing the Delis hierarchical processing task, subjects are asked to copy a large global figure made of smaller local forms. Both Down syndrome (DS) and William-Beuren syndrome (WBS) groups fail but in different ways. WBS individuals produce the local elements and DS individuals produce only the global forms. PMID: 12952863 Hum Mol Genet.

William-Beuren syndrome - (WBS) rare developmental disorder (1/20,000–1/50,000 live births). A contiguous gene deletion syndrome resulting from the hemizygous deletion of several genes on chromosome 7q11.23. The syndrome has associated craniofacial abnormalities, hypersociability and visuospatial defects. OMIM: William-Beuren syndrome

Search

• Bookshelf muscle development | muscle fiber type | troponin

• Pubmed muscle fiber type | troponin | Gtf2ird1 |

External Links

External Links Notice - The dynamic nature of the internet may mean that some of these listed links may no longer function. If the link no longer works search the web with the link text or name. Links to any external commercial sites are provided for information purposes only and should never be considered an endorsement. UNSW Embryology is provided as an educational resource with no clinical information or commercial affiliation.

• Blue Histology Skeletal Muscle histology
• Primer Skeletal Muscle Fiber Type: Influence on Contractile and Metabolic Properties
• Gray's Anatomy of the Human Body - The Muscles and Fasciæ of the Leg | Cross-section through middle of leg
• Wiki Skeletal muscle | Troponin
• OMIM: Gtf2ird1
• OMIM: William-Beuren syndrome

Individual Assessment

• Each student should now look at each of the other Group projects in the class.
• Next prepare a critical assessment (should include both positive and negative issues) of each project using the project group assessment criteria.
• This assessment should be pasted without signature on the top of the specific project's discussion page. (minimum length 3-5 paragraphs/project)
• This critical assessment should also be pasted on your own student page.
• Each student should therefore have 5 separate reports pasted on their own page for this assessment item.
• Length, quality and accuracy of your reports will be part of the overall mark for this assessment.
  • there will be a greater loading on this than simple question assessments.

Group Assessment Criteria

The key points relating to the topic that your group allocated are clearly described. The choice of content, headings and sub-headings, diagrams, tables, graphs show a good understanding of the topic area. Content is correctly cited and referenced. The wiki has an element of teaching at a peer level using the student's own innovative diagrams, tables or figures and/or using interesting examples or explanations. Evidence of significant research relating to basic and applied sciences that goes beyond the formal teaching activities. Relates the topic and content of the Wiki entry to learning aims of embryology. Clearly reflects on editing/feedback from group peers and articulates how the Wiki could be improved (or not) based on peer comments/feedback. Demonstrates an ability to review own work when criticised in an open edited wiki format. Reflects on what was learned from the process of editing a peer's wiki. Evaluates own performance and that of group peers to give a rounded summary of this wiki process in terms of group effort and achievement. The content of the wiki should demonstrate to the reader that your group has researched adequately on this topic and covered the key areas necessary to inform your peers in their learning. Develops and edits the wiki entries in accordance with the above guidelines.

Group Project

• Peer Assessment of projects.
• Please wait until all peer assessments have been submitted before making any changes to your project content.
• Note that following the peer assessment process, your group can then make changes based upon peer feedback.

Plagiarism

Currently all students originally assigned to each group are listed as equal authors/contributors to their project. If you have not contributed the content you had originally agreed to, nor participated in the group work process, then you should contact the course coordinator immediately and either discuss your contribution or request removal from the group author list. Remember that all student online contributions are recorded by date, time and the actual contributed content. A similar email reminder will be sent to all current students.

Please note the Universities Policy regarding Plagiarism

In particular this example:

"Claiming credit for a proportion of work contributed to a group assessment item that is greater than that actually contributed;"

Academic Misconduct carries penalties. If a student is found guilty of academic misconduct, the penalties include warnings, remedial educative action, being failed in an assignment or excluded from the University for two years.

Stem Cell Paper Preparation

As part of the assessment for this course, you will give a 15 minutes journal club presentation in the lab (30 October 2015). For this you will have to form student groups of 3 or 4, and discuss a recent (published after 2010) original research article (not a review!) on stem cell biology or technology.

Please tell Annemiek the composition of the groups, or send to her by email (A.Beverdam@unsw.edu.au) before the start of the next lecture, 1 pm on 26 October.

Each group sends PDFs of 2-3 selected articles to Annemiek by 5 pm on Friday 23 October. She will select which of the chosen articles you will present, and inform you by Monday noon. Please note that the best articles are found in journals with the highest impact factors: Nature, Science, Cell, Cell Stem Cell, etc). Please contact Annemiek in case you are at a loss, and she will help you find one.

During the presentation it works best if one student discusses the introduction, the second the results section, and the third the discussion section. Please note that one slide takes about 1 minute to talk through. So do not use more than 15 to 20 slides total. Please read through attached document for tips for how to prepare a good presentation.

You will receive a group mark based on presentation content, insight and comprehension, and presentation and slide style.

Presentation Hints for Students

• Do not use cheat sheets and do not learn your presentation literally by heart. Make sure that you know and understand what you want to get across. Explain carefully. Use your slides as cheat sheets. Make eye contact with your audience and get a feel for whether they understand your story.
• Keep your presentation short and concise. Not every detail of the article needs to be discussed in the presentation, but limit it to the bare minimum that is required to get the main message of the article across. For instance, do not go into too much detail in method sections. Not all nitty-gritty detail of the results needs to be discussed. The less info your audience has to take in, the higher the chance that they will understand your story.
• Don’t just put your slides up while you are presenting, but talk your audience carefully through them. Slides are an indispensable part of the presentation. Each item on your slides should be relevant and addressed and highlighted with pointer, fingers, stick. Slide shows are indispensable for a presentation, as is the presenter. They should support and enhance a presentation, they should aid your audience in understanding.
• Talk your audience through each of the figures on your slides. Figures may be obvious to you, but not to your audience unless you explain them carefully. So explain what experiment has been carried out, and what is displayed in the figure:
  • on the X and Y-axes
  • what the bars represent in diagrams
  • the tissues/cell types displayed
  • the bands on Western blot, RNA and DNA gels,
  • What colors represent colors in immunostainings, etc etc.
• Please note that you only need to highlight this experimental detail that is necessary to get the main message of the figure across.
• Conclude a (results) slide with a concluding/summarizing remark that should cover the main message of this particular slide.
• Annotate the figures in your presentation carefully but sparingly. Label panels, axes, images etc so that figures are self-explicatory.
• Do not use too much text on your slides.
• To stay in control the presenter should flick through the slide show. Not another member of the team.
• If you didn’t understand the articles in depth, read a recent review or even go back to text books to acquire the basic knowledge. Also, if you discuss results of a crucial experiment but do not understand the technology. Please go back to the original references or your text books to read up on this technology. You should be on top of everything you say or write up in your slides.
• Stick to your time. Don’t make too many slides. Each slide should take about a minute on average to talk through. Try to avoid acronyms and abbreviation.

References

2015 Course: Week 2 Lecture 1 Lecture 2 Lab 1 | Week 3 Lecture 3 Lecture 4 Lab 2 | Week 4 Lecture 5 Lecture 6 Lab 3 | Week 5 Lecture 7 Lecture 8 Lab 4 | Week 6 Lecture 9 Lecture 10 Lab 5 | Week 7 Lecture 11 Lecture 12 Lab 6 | Week 8 Lecture 13 Lecture 14 Lab 7 | Week 9 Lecture 15 Lecture 16 Lab 8 | Week 10 Lecture 17 Lecture 18 Lab 9 | Week 11 Lecture 19 Lecture 20 Lab 10 | Week 12 Lecture 21 Lecture 22 Lab 11 | Week 13 Lecture 23 Lecture 24 Lab 12 | 2015 Projects: Three Person Embryos | Ovarian Hyper-stimulation Syndrome | Polycystic Ovarian Syndrome | Male Infertility | Oncofertility | Preimplantation Genetic Diagnosis | Students | Student Designed Quiz Questions | Moodle page