{"type": "root", "children": [{"type": "p", "children": [{"type": "t", "text": "\nThe provided abstracts (PubMed"}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": "focus on the role of tektin proteins, in particular TEKT4, in regulating sperm flagellar motion. TEKT4 is a conserved structural protein that localizes to sperm flagella and is critical for the coordinated beating necessary for effective forward progression. Without proper TEKT4 function, sperm exhibit uncoordinated flagellar strokes and an abnormal increase in ATP consumption, ultimately compromising fertility."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": "In the detailed analyses, TEKT4 is shown to associate specifically with the outer dense fibers of the sperm flagellum rather than with axonemal microtubules. Experimental observations reveal that in the absence of TEKT4, as demonstrated in knockout mouse models, there is a profound disruption in flagellar waveform propagation. This structural misregulation leads to subfertility due to impaired sperm motility that results from both mechanical inefficiencies and rapid depletion of intracellular energy reserves."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "2"}]}, {"type": "t", "text": "It is important to note that although the original query asked for a summary of the function of SNORD115-43, neither abstract provides any reference to or discussion of SNORD115-43. The literature at hand exclusively addresses the functional and anatomical contributions of TEKT4 in sperm flagellar dynamics, leaving the role of SNORD115-43 undetermined within this context."}, {"type": "fg", "children": [{"type": "fg_f", "ref": "1"}]}, {"type": "t", "text": ""}]}, {"type": "rg", "children": [{"type": "r", "ref": 1, "children": [{"type": "t", "text": "Angshumoy Roy, Yi-Nan Lin, Julio E Agno, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Absence of tektin 4 causes asthenozoospermia and subfertility in male mice."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "FASEB J (2007)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1096/fj.06-7035com"}], "href": "https://doi.org/10.1096/fj.06-7035com"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "17244819"}], "href": "https://pubmed.ncbi.nlm.nih.gov/17244819"}]}, {"type": "r", "ref": 2, "children": [{"type": "t", "text": "Hiroshi Iida, Yoshiko Honda, Takuya Matsuyama, et al. "}, {"type": "b", "children": [{"type": "t", "text": "Tektin 4 is located on outer dense fibers, not associated with axonemal tubulins of flagella in rodent spermatozoa."}]}, {"type": "t", "text": " "}, {"type": "i", "children": [{"type": "t", "text": "Mol Reprod Dev (2006)"}]}, {"type": "t", "text": " DOI: "}, {"type": "a", "children": [{"type": "t", "text": "10.1002/mrd.20486"}], "href": "https://doi.org/10.1002/mrd.20486"}, {"type": "t", "text": " PMID: "}, {"type": "a", "children": [{"type": "t", "text": "16596631"}], "href": "https://pubmed.ncbi.nlm.nih.gov/16596631"}]}]}]}