title: The characterisation and role of mighty during myogenesis

authors: Davies, Todd John

subjects: myogenesis

abstract: Myogenesis, or skeletal muscle formation, begins during embryogenesis and involves the proliferation of myoblasts followed by their exit from the cell-cycle to differentiate and form myotubes. This formation of skeletal muscle is a complex process involving many genes and various signalling pathways. Mighty is a novel myogenic gene discovered at AgResearch by the Functional Muscle Genomics (FMG) group in a genetic screen performed on the muscle of myostatin null and wild-type mice. It was found that heavily muscled mice, lacking myostatin, had increased expression of the mighty gene. This gene was found to be conserved, with cognates found in mammals, amphibians, teleosts, and arthropods. Mighty was found to be expressed in a variety of tissues, but only skeletal muscle showed increased mighty mRNA expression in myostatin null mice, indicating the specific regulation of mighty by myostatin in skeletal muscle (Marshall, 2005).

The aim of this study was to characterise the mighty protein and examine its role in myogenesis to elucidate mighty's function. To undertake this study, antibodies specific for the full-length mighty protein and antibodies specific for a peptide region of mighty were characterised. Results using these antibodies, showed endogenous mighty, from myoblasts, to be a low-abundant, nuclear protein which shows a mobility of ~52 kDa in SDS gels, different to that of recombinant mighty protein. The mobility difference of endogenous mighty compared to recombinant mighty appears to be due to phosphorylation and may involve other post-translational modifications. In agreement, the determined isoelectric point (~5.7) of endogenous mighty also appears to be the result of phosphorylation. Interestingly, 52 kDa mighty was not detected in muscle extracts, but a ~30 kDa protein was specifically detected, indicating multiple forms, and subsequent roles, for mighty protein. Mass spectrometry (MS) was also performed for further characterisation of the mighty protein and possible post-translational modifications. Although hits were achieved with both recombinant mighty proteins, endogenous mighty MS analysis was not accomplished due to its low-abundance.

The function of the mighty protein in myoblasts was investigated during proliferation and differentiation. The results indicate that proliferating myoblasts have low levels of mighty in G0 and increased levels in G1/S during the cell cycle. This differential expression of mighty may involve cell cycle exit at the G1/S phase. Differentiation results showed mighty to be upregulated before MyoD during differentiation, placing mighty very early in the differentiation hierarchy. This agrees with previous results by Marshall (2005) which showed mighty to upregulate MyoD through IGF-II expression. Enhanced differentiation was also seen in double muscle bovine myoblasts concomitantly with increased mighty expression.

In conclusion, mighty appears to be a post-translationally modified protein that plays an early role in myogenic differentiation. This role in differentiation appears to be upstream of MyoD through the upregulation of IGF-II and may be linked to cell cycle exit in the G1 phase of the cell cycle.

text: The characterisation and role of mighty during myogenesis Myogenesis, or skeletal muscle formation, begins during embryogenesis and involves the proliferation of myoblasts followed by their exit from the cell-cycle to differentiate and form myotubes. This formation of skeletal muscle is a complex process involving many genes and various signalling pathways. Mighty is a novel myogenic gene discovered at AgResearch by the Functional Muscle Genomics (FMG) group in a genetic screen performed on the muscle of myostatin null and wild-type mice. It was found that heavily muscled mice, lacking myostatin, had increased expression of the mighty gene. This gene was found to be conserved, with cognates found in mammals, amphibians, teleosts, and arthropods. Mighty was found to be expressed in a variety of tissues, but only skeletal muscle showed increased mighty mRNA expression in myostatin null mice, indicating the specific regulation of mighty by myostatin in skeletal muscle (Marshall, 2005).

The aim of this study was to characterise the mighty protein and examine its role in myogenesis to elucidate mighty's function. To undertake this study, antibodies specific for the full-length mighty protein and antibodies specific for a peptide region of mighty were characterised. Results using these antibodies, showed endogenous mighty, from myoblasts, to be a low-abundant, nuclear protein which shows a mobility of ~52 kDa in SDS gels, different to that of recombinant mighty protein. The mobility difference of endogenous mighty compared to recombinant mighty appears to be due to phosphorylation and may involve other post-translational modifications. In agreement, the determined isoelectric point (~5.7) of endogenous mighty also appears to be the result of phosphorylation. Interestingly, 52 kDa mighty was not detected in muscle extracts, but a ~30 kDa protein was specifically detected, indicating multiple forms, and subsequent roles, for mighty protein. Mass spectrometry (MS) was also performed for further characterisation of the mighty protein and possible post-translational modifications. Although hits were achieved with both recombinant mighty proteins, endogenous mighty MS analysis was not accomplished due to its low-abundance.

The function of the mighty protein in myoblasts was investigated during proliferation and differentiation. The results indicate that proliferating myoblasts have low levels of mighty in G0 and increased levels in G1/S during the cell cycle. This differential expression of mighty may involve cell cycle exit at the G1/S phase. Differentiation results showed mighty to be upregulated before MyoD during differentiation, placing mighty very early in the differentiation hierarchy. This agrees with previous results by Marshall (2005) which showed mighty to upregulate MyoD through IGF-II expression. Enhanced differentiation was also seen in double muscle bovine myoblasts concomitantly with increased mighty expression.

In conclusion, mighty appears to be a post-translationally modified protein that plays an early role in myogenic differentiation. This role in differentiation appears to be upstream of MyoD through the upregulation of IGF-II and may be linked to cell cycle exit in the G1 phase of the cell cycle.

year: 2006

title: Exemplary teachers' approaches to supporting vocabulary development during shared reading

authors: Oliver, John-Paul

subjects: shared reading

abstract: An analysis of recent PIRLS (Progress in International Reading Literacy Study) data has shown that a group of New Zealand children are struggling to learn to read well. Vocabulary knowledge supports reading in a number of ways and research shows that reading to children and discussing texts with them helps support the development of vocabulary knowledge. This study sought to examine how four exemplary teachers of junior classes in two primary schools went about supporting the vocabulary development of their students during shared reading. The teachers completed a questionnaire and were then observed undertaking 30 shared reading lessons. They were then interviewed about their perceptions regarding vocabulary support during shared reading. Results showed that on average these teachers committed over 20% of their shared reading sessions to vocabulary development during shared reading, although there was some variation between teachers. These teachers supported their students learning of word meanings via a balanced range of avenues for acquiring vocabulary and used a rich and varied range of instructional methods to convey and secure vocabulary knowledge during shared reading. The teachers indicated that they believed that shared reading was an important context for providing support for vocabulary and that providing support for vocabulary in a balanced range of ways was important. Results are discussed in relation to recent literature pertaining to vocabulary acquisition and supporting the vocabulary development of children while reading to them.

text: Exemplary teachers' approaches to supporting vocabulary development during shared reading An analysis of recent PIRLS (Progress in International Reading Literacy Study) data has shown that a group of New Zealand children are struggling to learn to read well. Vocabulary knowledge supports reading in a number of ways and research shows that reading to children and discussing texts with them helps support the development of vocabulary knowledge. This study sought to examine how four exemplary teachers of junior classes in two primary schools went about supporting the vocabulary development of their students during shared reading. The teachers completed a questionnaire and were then observed undertaking 30 shared reading lessons. They were then interviewed about their perceptions regarding vocabulary support during shared reading. Results showed that on average these teachers committed over 20% of their shared reading sessions to vocabulary development during shared reading, although there was some variation between teachers. These teachers supported their students learning of word meanings via a balanced range of avenues for acquiring vocabulary and used a rich and varied range of instructional methods to convey and secure vocabulary knowledge during shared reading. The teachers indicated that they believed that shared reading was an important context for providing support for vocabulary and that providing support for vocabulary in a balanced range of ways was important. Results are discussed in relation to recent literature pertaining to vocabulary acquisition and supporting the vocabulary development of children while reading to them.

year: 2014

title: Maori participation in higher education: Tainui graduates from the University of Waikato, 1992 to 1997

authors: Tiakiwai, Sarah-Jane

abstract: This thesis is an examination of what factors contribute to the success of Maori who participate in higher education. The thesis is informed by the experiences of nine Tainui tribal members who received scholarships from the Tainui Maori Trust Board and who graduated from the University of Waikato between 1992 and 1997. 

The thesis addresses two questions: what factors contributed to the success of Tainui graduates at the University of Waikato? What effect did programmes, policies and initiatives offered by the University of Waikato and the Tainui Maori Trust Board have on the academic success of Tainui graduates at the University of Waikato? 

There are three main components to the thesis: a brief history of the University of Waikato and an examination of three documents (University of Waikato Charter 1991; Paetawhiti, the strategic plan 1993; Academic Audit Unit report 1997) and how they pertain to Maori; a history of the Tainui Maori Trust Board and an examination of the Tainui Education Strategy (1986, 1991), its review (1993) and scholarship programmes; and a study and analysis of the experiences of nine Tainui graduates from the University of Waikato. 

Argued from an eclectic theoretical and methodological position, drawing from indigenous and western theories and research practices that emphasise a kaupapa Maori and tribal approach, the thesis identifies multiple factors that have contributed to the success of the Tainui graduates. These factors include family and parental support, mentoring, the role of finances, institutional support, and identity. 

The thesis finds through examination of the documents, that the policies, initiatives and programmes of the Tainui Maori Trust Board and the University of Waikato have ambiguous and at times conflicting aims and objectives in regard to Maori participation and graduation from higher education. The thesis also finds that the experiences of the graduates reveal that neither the Tainui Maori Trust Board nor policies relating to Maori at the University of Waikato played significant roles in the success of the Tainui graduates. Rather, the thesis finds that the success of the graduates is largely borne by their own efforts, which reflect western notions of success, but which also reinforce their identity as Maori, and as Tainui tribal members. 

The thesis suggests that both the Tainui Maori Trust Board and the University of Waikato review their relationships with their tribal and Maori members (respectively), and recommendations are made to help develop a greater awareness of the contribution that both organisations can make to the success of Maori university students.

text: Maori participation in higher education: Tainui graduates from the University of Waikato, 1992 to 1997 This thesis is an examination of what factors contribute to the success of Maori who participate in higher education. The thesis is informed by the experiences of nine Tainui tribal members who received scholarships from the Tainui Maori Trust Board and who graduated from the University of Waikato between 1992 and 1997. 

The thesis addresses two questions: what factors contributed to the success of Tainui graduates at the University of Waikato? What effect did programmes, policies and initiatives offered by the University of Waikato and the Tainui Maori Trust Board have on the academic success of Tainui graduates at the University of Waikato? 

There are three main components to the thesis: a brief history of the University of Waikato and an examination of three documents (University of Waikato Charter 1991; Paetawhiti, the strategic plan 1993; Academic Audit Unit report 1997) and how they pertain to Maori; a history of the Tainui Maori Trust Board and an examination of the Tainui Education Strategy (1986, 1991), its review (1993) and scholarship programmes; and a study and analysis of the experiences of nine Tainui graduates from the University of Waikato. 

Argued from an eclectic theoretical and methodological position, drawing from indigenous and western theories and research practices that emphasise a kaupapa Maori and tribal approach, the thesis identifies multiple factors that have contributed to the success of the Tainui graduates. These factors include family and parental support, mentoring, the role of finances, institutional support, and identity. 

The thesis finds through examination of the documents, that the policies, initiatives and programmes of the Tainui Maori Trust Board and the University of Waikato have ambiguous and at times conflicting aims and objectives in regard to Maori participation and graduation from higher education. The thesis also finds that the experiences of the graduates reveal that neither the Tainui Maori Trust Board nor policies relating to Maori at the University of Waikato played significant roles in the success of the Tainui graduates. Rather, the thesis finds that the success of the graduates is largely borne by their own efforts, which reflect western notions of success, but which also reinforce their identity as Maori, and as Tainui tribal members. 

The thesis suggests that both the Tainui Maori Trust Board and the University of Waikato review their relationships with their tribal and Maori members (respectively), and recommendations are made to help develop a greater awareness of the contribution that both organisations can make to the success of Maori university students.

year: 2001