title: Targets of Elf5 in Mouse Trophoblast Stem Cells

authors: Deane, Jessica Robyn

subjects: Elf5

abstract: The Placenta is an essential organ for all mammalian embryonic development as it provides the nutritional link between maternal and foetal blood streams. The cells which go on to proliferate and contribute to all the major cell types of the embryo derived placenta have been located to the trophoblast (TE) cells overlying the Inner Cell Mass (ICM) of the embryo. Immortal cell lines have been subsequentially derived from this tissue and called Trophoblast Stem (TS) cells. In parallel with their  in vivo  counterparts they are also reliant on Fibroblast growth factor 4 (FgF4) (Tanaka et al., 1998) and Activin/Nodal signalling (Guzman-Ayala et al., 2004). 

The Ets family transcription factor, Elf5, has been shown to be specifically expressed in the early placental trophoblast and subsequent derived tissues. Mice deficient in Elf5 failed to form a placenta post implantation. Furthermore TS cells were unable to be derived from Elf5 knockout embryos (Donnison et al., 2005). This work suggested that Elf5 plays an essential role in TS cells and their differentiation. The aim of this study was to determine the downstream target genes of Elf5 in mouse TS cells. The target genes of Fgf4 and Activin/Nodal signalling in TS cells were also investigated.  This work is hoped to contribute to an overall greater understanding of the molecular networks underlying TS cell maintenance and to contribute to our knowledge of early placental development. 

Small interfering RNA (siRNA) targeted reduction of Elf5 mRNA expression in mTS cells was achieved using two independent siRNAs; with Elf5 reduction exceeding 80%. The resulting changes in gene expression were measured in order to determine the downstream targets of Elf5. Selected genes known to be important for trophoblast differentiation and maintenance were measured using real-time PCR in a candidate gene approach .Global changes in gene expression as a consequence of Elf5 silencing were measured using an Affymetrix microarray. Global changes in gene expression due to growth factor (Fgf4 and/or Activin) removal were also measured. Expression of 22 genes was changed using either of the Elf5 siRNA oligonucleotides. Of these, 9 were also significantly changed by growth factor removal. Included in this set were Synopl, Hst3st3b1, Cyr61 and Sox2. In the overall analysis, many genes whose expression changed upon loss of Elf5 are known to play important roles in trophectoderm cell specification. Real-time PCR validation agreed closely with the up or down regulation measured using the microarray. This work has thus led to the discovery of sets of Elf5 target genes potentially involved in trophoblast stem cell function and has provided the foundation for future work exploring the molecular pathways of trophoblast development.

text: Targets of Elf5 in Mouse Trophoblast Stem Cells The Placenta is an essential organ for all mammalian embryonic development as it provides the nutritional link between maternal and foetal blood streams. The cells which go on to proliferate and contribute to all the major cell types of the embryo derived placenta have been located to the trophoblast (TE) cells overlying the Inner Cell Mass (ICM) of the embryo. Immortal cell lines have been subsequentially derived from this tissue and called Trophoblast Stem (TS) cells. In parallel with their  in vivo  counterparts they are also reliant on Fibroblast growth factor 4 (FgF4) (Tanaka et al., 1998) and Activin/Nodal signalling (Guzman-Ayala et al., 2004). 

The Ets family transcription factor, Elf5, has been shown to be specifically expressed in the early placental trophoblast and subsequent derived tissues. Mice deficient in Elf5 failed to form a placenta post implantation. Furthermore TS cells were unable to be derived from Elf5 knockout embryos (Donnison et al., 2005). This work suggested that Elf5 plays an essential role in TS cells and their differentiation. The aim of this study was to determine the downstream target genes of Elf5 in mouse TS cells. The target genes of Fgf4 and Activin/Nodal signalling in TS cells were also investigated.  This work is hoped to contribute to an overall greater understanding of the molecular networks underlying TS cell maintenance and to contribute to our knowledge of early placental development. 

Small interfering RNA (siRNA) targeted reduction of Elf5 mRNA expression in mTS cells was achieved using two independent siRNAs; with Elf5 reduction exceeding 80%. The resulting changes in gene expression were measured in order to determine the downstream targets of Elf5. Selected genes known to be important for trophoblast differentiation and maintenance were measured using real-time PCR in a candidate gene approach .Global changes in gene expression as a consequence of Elf5 silencing were measured using an Affymetrix microarray. Global changes in gene expression due to growth factor (Fgf4 and/or Activin) removal were also measured. Expression of 22 genes was changed using either of the Elf5 siRNA oligonucleotides. Of these, 9 were also significantly changed by growth factor removal. Included in this set were Synopl, Hst3st3b1, Cyr61 and Sox2. In the overall analysis, many genes whose expression changed upon loss of Elf5 are known to play important roles in trophectoderm cell specification. Real-time PCR validation agreed closely with the up or down regulation measured using the microarray. This work has thus led to the discovery of sets of Elf5 target genes potentially involved in trophoblast stem cell function and has provided the foundation for future work exploring the molecular pathways of trophoblast development.

year: 2007

title: A farmer's perspective

authors: Morrison, Stuart

abstract: Stuart’s family came to farm in the Rotorua area in 1965. After a time away, including pursuing a career in industry, he returned. He has been dairy farming in the Lake Rotorua catchment for more than 30 years. He has been interested in, and part of the discussions about the lake and its catchment for a lot of that time, more particularly in recent years.

text: A farmer's perspective Stuart’s family came to farm in the Rotorua area in 1965. After a time away, including pursuing a career in industry, he returned. He has been dairy farming in the Lake Rotorua catchment for more than 30 years. He has been interested in, and part of the discussions about the lake and its catchment for a lot of that time, more particularly in recent years.

year: 2013

title: Perceptions, expectations and interactions: a study of teachers and pupils in five ethnically mixed primary classrooms

authors: St George, Alison

abstract: Teachers’ perceptions of their pupils, expectations for pupil general ability, teacher-pupil interaction and pupil achievement were investigated in this naturalistic study of 5 teachers and 90 pupils in their New Zealand ethnically mixed Standard 3 classrooms.
A pilot study showed that teachers at this level tended to perceive pupils in terms of constructs reflecting academic work skills, home background and personal/social attributes. Using rating scales developed from the pilot study it was apparent that the teachers had a conception of the ideal pupil. It was suggested that this influenced expectations for pupils’ ability to do well at school. Girls and Pakeha pupils were seen as being closer to the ideal pupil stereotype than boys or Polynesian pupils, and for Polynesian pupils this was reflected in lower teacher expectations. Teacher expectations tended to be borne out by standardized achievement test results and accounted for a large proportion of teacher rated achievement variance. Ethnic group made a small but significant independent contribution to achievement variance on two of the Progressive Achievement Tests and on teacher rated achievement.
Using data on teacher-pupil dyadic interaction collected with the Brophy-Good system, contrasting patterns of interaction were noted between expectation groups (high, middle and low teacher expectations). The differences were largely qualitative and there were no expectation group differences in the total number of public or private dyadic interactions. High expectation pupils initiated more contacts with the teacher, answered more open public academic questions and received a lot less criticism for work or behaviour than the other groups. The low expectation group experienced a greater proportion of teacher initiated contacts and were asked more direct public academic questions which were of the product rather than the process type. The middle expectation group generally fell in between the high and low groups, but received the most criticism and the highest proportion of process questions. Teachers appeared to be attempting to prevent inequalities in quantity of interaction and this was discussed in terms of the perception of pupil attributes. Expectation group differences in interaction were not always the same for boys and girls or for all teachers. Despite the differences in teachers’ perceptions and expectations for Polynesian and Pakeha pupils, no ethnic group differences in teacher-pupil interaction were evidenced. 
No consistent and clear-cut expectation group differences were found in pupils’ perceptions of teacher behaviour. There was a moderate positive correlation between perception of the quantity of teacher contact and observed interaction but not regarding the affective quality of teacher contacts. 
The findings were discussed in terms of the theory and research on person perception and expectation phenomena in interpersonal behaviour. Some practical implications for educational practice were commented upon.

text: Perceptions, expectations and interactions: a study of teachers and pupils in five ethnically mixed primary classrooms Teachers’ perceptions of their pupils, expectations for pupil general ability, teacher-pupil interaction and pupil achievement were investigated in this naturalistic study of 5 teachers and 90 pupils in their New Zealand ethnically mixed Standard 3 classrooms.
A pilot study showed that teachers at this level tended to perceive pupils in terms of constructs reflecting academic work skills, home background and personal/social attributes. Using rating scales developed from the pilot study it was apparent that the teachers had a conception of the ideal pupil. It was suggested that this influenced expectations for pupils’ ability to do well at school. Girls and Pakeha pupils were seen as being closer to the ideal pupil stereotype than boys or Polynesian pupils, and for Polynesian pupils this was reflected in lower teacher expectations. Teacher expectations tended to be borne out by standardized achievement test results and accounted for a large proportion of teacher rated achievement variance. Ethnic group made a small but significant independent contribution to achievement variance on two of the Progressive Achievement Tests and on teacher rated achievement.
Using data on teacher-pupil dyadic interaction collected with the Brophy-Good system, contrasting patterns of interaction were noted between expectation groups (high, middle and low teacher expectations). The differences were largely qualitative and there were no expectation group differences in the total number of public or private dyadic interactions. High expectation pupils initiated more contacts with the teacher, answered more open public academic questions and received a lot less criticism for work or behaviour than the other groups. The low expectation group experienced a greater proportion of teacher initiated contacts and were asked more direct public academic questions which were of the product rather than the process type. The middle expectation group generally fell in between the high and low groups, but received the most criticism and the highest proportion of process questions. Teachers appeared to be attempting to prevent inequalities in quantity of interaction and this was discussed in terms of the perception of pupil attributes. Expectation group differences in interaction were not always the same for boys and girls or for all teachers. Despite the differences in teachers’ perceptions and expectations for Polynesian and Pakeha pupils, no ethnic group differences in teacher-pupil interaction were evidenced. 
No consistent and clear-cut expectation group differences were found in pupils’ perceptions of teacher behaviour. There was a moderate positive correlation between perception of the quantity of teacher contact and observed interaction but not regarding the affective quality of teacher contacts. 
The findings were discussed in terms of the theory and research on person perception and expectation phenomena in interpersonal behaviour. Some practical implications for educational practice were commented upon.

year: 1978